less strict validation of email addresses

E-mail addresses are currently validated with classes provided by [commons-validator](https://commons.apache.org/validator/) when XML is read or written. This validator does not handle new top level domains (nTLD) properly. Therefore the validation is replaced by a more simple approach, that validates the e-mail address against the pattern, that is specified by IS24 in `common-1.0.xsd`.

```
  <xs:simpleType name="Email">
    <xs:annotation>
      <xs:documentation xml:lang="en">Common email address with restriction of 300 chars.</xs:documentation>
      <xs:documentation xml:lang="de-DE">Emailadresse mit einer 300 Zeichen Längenbegrenzung.
      </xs:documentation>
    </xs:annotation>
    <xs:restriction base="xs:string">
      <xs:minLength value="5"/>
      <xs:maxLength value="300"/>
      <xs:pattern value=".+@.+\..+"></xs:pattern>
    </xs:restriction>
  </xs:simpleType>
```

CHANGELOG.md

@@ -5,7 +5,21 @@ Changelog for OpenEstate-IS24-REST
 0.4-SNAPSHOT (not released yet)
 -------------------------------
 
-...
+### bugfixes
+
+-   Less strict validation of e-mail addresses.
+    E-mail addresses are currently validated with classes provided by
+    [commons-validator](https://commons.apache.org/validator/) when XML is read
+    or written. This validator does not handle new top level domains (nTLD)
+    properly. Therefore the validation is replaced by a more simple approach,
+    that validates the e-mail address against the pattern, that is specified by
+    IS24 in `common-1.0.xsd`.
+
+### updates
+
+-   The package `org.openestate.is24.restapi.utils.validator`, that contains
+    some classes of [commons-validator](https://commons.apache.org/validator/),
+    was removed from source code.
 
 
 0.3.1 (10 Mar 2016)

OpenEstate-IS24-REST/src/main/java/org/openestate/is24/restapi/utils/XmlUtils.java

@@ -45,7 +45,6 @@
 import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.lang3.SystemUtils;
 import org.apache.commons.lang3.time.DateUtils;
-import org.openestate.is24.restapi.utils.validator.EmailValidator;
 import org.openestate.is24.restapi.xml.common.Attachment;
 import org.openestate.is24.restapi.xml.common.City;
 import org.openestate.is24.restapi.xml.common.Continent;
@@ -107,6 +106,8 @@ public final class XmlUtils
     "<[^<>\\n]*>", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE );
   private final static Pattern BR_TAG_PATTERN = Pattern.compile(
     "<\\s*br[^<>\\n]*>", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE );
+  private final static Pattern EMAIL_PATTERN = Pattern.compile(
+    ".+@.+\\..+", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE );
 
   private XmlUtils()
   {
@@ -430,7 +431,7 @@ public static String parseEmail( String value )
   {
     String val = parseText( value, 5, 300 );
     if (val==null) return null;
-    return (EmailValidator.getInstance().isValid( val ))? val: null;
+    return (EMAIL_PATTERN.matcher( val ).matches())? val: null;
   }
 
   /**
@@ -1193,7 +1194,7 @@ public static String printDecimalPositive( BigDecimal value )
   public static String printEmail( String value )
   {
     String val = printText( value, 5, 300 );
-    if (val==null || !EmailValidator.getInstance().isValid( val ))
+    if (val==null || !EMAIL_PATTERN.matcher( val ).matches())
     {
       throw new IllegalArgumentException(
         "The provided email '" + value + "' is invalid!" );