Added ant build script. Fixes issue 23.

.gitignore

@@ -1,2 +1,3 @@
 {8620c15f-30dc-4dba-a131-7c5d20cf4a29}
 *.xpi
+.DS_Store

README.md

@@ -19,11 +19,17 @@ then add a file titled '{8620c15f-30dc-4dba-a131-7c5d20cf4a29}' to the "extensio
 
 or whatever the path to your nightlytt folder is.
 
-To bundle the extension into an xpi for distribution, run this command to get a `nightlytt.xpi` file:
+To package the extension into an xpi for distribution simply `ant` and the default build script/target will be invoked:
 
-```
-cd extension; zip -r ../nightlytt.xpi * -x@../zipexclude.lst; cd ..
-```
+    ant
+
+You can override the build number used in the filename:
+
+    ant -Dbuild.number=1
+
+To build for release (no build version in filename):
+
+    ant -Drelease=true
 
 # Development
 All bugs are reported to the Nightly Tester Tools component at bugzilla.mozilla.org. [bug list](https://bugzilla.mozilla.org/buglist.cgi?query_format=advanced&component=Nightly%20Tester%20Tools&product=Other%20Applications), [file a bug](https://bugzilla.mozilla.org/enter_bug.cgi?product=Other%20Applications&component=Nightly%20Tester%20Tools). Check out [the wiki](https://wiki.mozilla.org/Auto-tools/Projects/NightlyTesterTools) for a list of current and proposed features and feel free to file bugs and submit patches.

build.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0"?>
+
+<project name="nightlytt" default="package">
+  <tstamp>
+    <format property="build.number" pattern="yyyyMMddHHmm"/>
+  </tstamp>
+
+  <target name="getversion" unless="build.version">
+    <xmlproperty file="extension/install.rdf" collapseAttributes="true"/>
+    <property name="build.version" value="${RDF.Description.em:version}"/>
+    <echo>build.version: ${build.version}</echo>
+  </target>
+
+  <target name="package" depends="getversion">
+    <condition property="package.filename" value="${ant.project.name}-${build.version}.xpi">
+      <isset property="release"/>
+    </condition>
+    <property name="package.filename" value="${ant.project.name}-${build.version}-${build.number}.xpi"/>
+    <delete file="${package.filename}"/>
+    <zip destfile="${package.filename}" basedir="extension" excludesfile=".gitignore"/>
+    <echo>package.filename: ${package.filename}</echo>
+  </target>
+
+</project>