- new support library GitComInf to generate a property file for use in Gradle
- adjusted build.gradle to make use of it to create the yacyBuildProperties.java
- including additon of properties ext.filterTokens as store for Gradle
- added gradle-compile-htroot (w/o depends) to old build.xml as target until complete migration
as it is imho important
imho: much to complicated to get a running number - should be supplied by repo or simplified