Follow up for elastic#84.

Sounds like that httpcore is pulled by netcdf libs. Note that we wrote in elastic#84 that we were removing support for netcdf file types.

```xml
<!-- Not Apache2 License compatible -->
<exclusion>
    <groupId>edu.ucar</groupId>
    <artifactId>netcdf</artifactId>
</exclusion>
```

Apparently the removal was not entirely done.

Adding exclusion the following exclusions will fix that:

```xml
<!-- Not Apache2 License compatible -->
<exclusion>
    <groupId>edu.ucar</groupId>
    <artifactId>cdm</artifactId>
</exclusion>
<!-- Not Apache2 License compatible -->
<exclusion>
    <groupId>edu.ucar</groupId>
    <artifactId>httpservices</artifactId>
</exclusion>
<!-- Not Apache2 License compatible -->
<exclusion>
    <groupId>edu.ucar</groupId>
    <artifactId>grib</artifactId>
</exclusion>
<!-- Not Apache2 License compatible -->
<exclusion>
    <groupId>edu.ucar</groupId>
    <artifactId>netcdf4</artifactId>
</exclusion>
```

With that, we don't pull anymore http* client/core/component libs:

```
[INFO] org.elasticsearch:elasticsearch-mapper-attachments:jar:2.7.1-SNAPSHOT
...
[INFO] +- org.apache.tika:tika-parsers:jar:1.10:compile
[INFO] |  +- org.apache.tika:tika-core:jar:1.10:compile
[INFO] |  +- org.gagravarr:vorbis-java-tika:jar:0.6:compile
[INFO] |  +- com.healthmarketscience.jackcess:jackcess:jar:2.1.2:compile
[INFO] |  |  +- commons-lang:commons-lang:jar:2.6:compile
[INFO] |  |  \- commons-logging:commons-logging:jar:1.1.3:compile
[INFO] |  +- com.healthmarketscience.jackcess:jackcess-encrypt:jar:2.1.0:compile
[INFO] |  +- net.sourceforge.jmatio:jmatio:jar:1.0:compile
[INFO] |  +- org.apache.james:apache-mime4j-core:jar:0.7.2:compile
[INFO] |  +- org.apache.james:apache-mime4j-dom:jar:0.7.2:compile
[INFO] |  +- org.apache.commons:commons-compress:jar:1.9:compile
[INFO] |  +- org.tukaani:xz:jar:1.5:compile
[INFO] |  +- commons-codec:commons-codec:jar:1.9:compile
[INFO] |  +- org.apache.pdfbox:pdfbox:jar:1.8.10:compile
[INFO] |  |  +- org.apache.pdfbox:fontbox:jar:1.8.10:compile
[INFO] |  |  \- org.apache.pdfbox:jempbox:jar:1.8.10:compile
[INFO] |  +- org.bouncycastle:bcmail-jdk15on:jar:1.52:compile
[INFO] |  |  \- org.bouncycastle:bcpkix-jdk15on:jar:1.52:compile
[INFO] |  +- org.bouncycastle:bcprov-jdk15on:jar:1.52:compile
[INFO] |  +- org.apache.poi:poi:jar:3.13-beta1:compile
[INFO] |  +- org.apache.poi:poi-scratchpad:jar:3.13-beta1:compile
[INFO] |  +- org.apache.poi:poi-ooxml:jar:3.13-beta1:compile
[INFO] |  |  \- org.apache.poi:poi-ooxml-schemas:jar:3.13-beta1:compile
[INFO] |  |     \- org.apache.xmlbeans:xmlbeans:jar:2.6.0:compile
[INFO] |  +- org.ccil.cowan.tagsoup:tagsoup:jar:1.2.1:compile
[INFO] |  +- com.googlecode.mp4parser:isoparser:jar:1.0.2:compile
[INFO] |  |  \- org.aspectj:aspectjrt:jar:1.8.0:compile
[INFO] |  +- com.drewnoakes:metadata-extractor:jar:2.8.0:compile
[INFO] |  |  \- com.adobe.xmp:xmpcore:jar:5.1.2:compile
[INFO] |  +- de.l3s.boilerpipe:boilerpipe:jar:1.1.0:compile
[INFO] |  +- rome:rome:jar:1.0:compile
[INFO] |  |  \- jdom:jdom:jar:1.0:compile
[INFO] |  +- org.gagravarr:vorbis-java-core:jar:0.6:compile
[INFO] |  +- com.googlecode.juniversalchardet:juniversalchardet:jar:1.0.3:compile
[INFO] |  +- org.codelibs:jhighlight:jar:1.0.2:compile
[INFO] |  +- com.pff:java-libpst:jar:0.8.1:compile
[INFO] |  +- com.github.junrar:junrar:jar:0.7:compile
[INFO] |  |  \- org.apache.commons:commons-vfs2:jar:2.0:compile
[INFO] |  |     +- org.apache.maven.scm:maven-scm-api:jar:1.4:compile
[INFO] |  |     |  \- org.codehaus.plexus:plexus-utils:jar:1.5.6:compile
[INFO] |  |     \- org.apache.maven.scm:maven-scm-provider-svnexe:jar:1.4:compile
[INFO] |  |        +- org.apache.maven.scm:maven-scm-provider-svn-commons:jar:1.4:compile
[INFO] |  |        \- regexp:regexp:jar:1.3:compile
[INFO] |  +- org.apache.opennlp:opennlp-tools:jar:1.5.3:compile
[INFO] |  |  +- org.apache.opennlp:opennlp-maxent:jar:3.0.3:compile
[INFO] |  |  \- net.sf.jwordnet:jwnl:jar:1.3.3:compile
[INFO] |  +- commons-io:commons-io:jar:2.4:compile
[INFO] |  +- org.apache.commons:commons-exec:jar:1.3:compile
[INFO] |  +- com.googlecode.json-simple:json-simple:jar:1.1.1:compile
[INFO] |  +- com.google.guava:guava:jar:18.0:compile
[INFO] |  +- org.apache.commons:commons-csv:jar:1.0:compile
[INFO] |  +- org.apache.sis.core:sis-utility:jar:0.5:compile
[INFO] |  +- org.apache.sis.storage:sis-netcdf:jar:0.5:compile
[INFO] |  |  +- org.apache.sis.storage:sis-storage:jar:0.5:compile
[INFO] |  |  \- org.apache.sis.core:sis-referencing:jar:0.5:compile
[INFO] |  +- org.apache.sis.core:sis-metadata:jar:0.5:compile
[INFO] |  \- org.opengis:geoapi:jar:3.0.0:compile
[INFO] |     \- javax.measure:jsr-275:jar:0.9.3:compile
[INFO] +- log4j:log4j:jar:1.2.17:compile
[INFO] \- org.elasticsearch:elasticsearch:test-jar:tests:1.7.0:test
```

Closes elastic#157

(cherry picked from commit 3eac5e6)

Closes elastic#157

Updated systemd template with the changes from the one that ships wit…

fixes elastic#157

This PR introduces a very slimmed down grammar with only one command row and expressions only consisting of integer literals.

The nature of the row command shouldn't matter too much and can easily be changed later. But it allows to test the parser end-to-end also using CSV Specs very similar to SQL's.

The parser has been bootstrapped using the same build tasks and structure as the EQL parser.

With this commit we purge the CDN cache for the page root (i.e. the path
`/`) as well as `/index.html`. Web browsers usually don't retrieve
`index.html` but rather page root and thus we need to purge the cache
for both to ensure users get a fresh copy.