remove errant files
add ability to get version info

html info and version string of geoserver
add tests, too
support for layergroups in 2.3, refs #47

the xml changed slightly, this depends on the version PR #46 to
provide fallback support for 2.2
Merge pull request #44 from ischneider/minor-cleanup

remove errant files
Merge pull request #46 from ischneider/get-version

add ability to get version info
Merge pull request #48 from ischneider/2.3-layer-group

2.3 layer group