Merge pull request #19 from akkie/master

Cross build for Scala 2.10 and 2.11
Added GzipFilter Warnign
Merge pull request #23 from sne11ius/add_gzip_warning

Added GzipFilter Warning
Merge remote-tracking branch 'origin/master'
Add XMLCompressionFilter
Merge pull request #25 from sne11ius/add_xml

Add XmlCompressorFilter
Some code simplifications