use version 1.7.6-scm4-SNAPSHOT of svnkit to fix issue #298

--HG--
branch : issue-298
update jgit to version 2.2.0.201212191850-r
update mustache to version 0.8.9
update enunciate to version 1.26.2
use final version of svnkit-1.7.6-scm4

--HG--
branch : issue-298
close branch issue-298

--HG--
branch : issue-298
extra : close : 1
merge with branch issue-298
register installed to local repository manager, to fix issue #306

--HG--
branch : issue-306
improve aether logging to find issue #299

--HG--
branch : issue-299
close branch issue-306

--HG--
branch : issue-306
extra : close : 1
merge with branch issue-306
remove unused imports
fix wrong javadoc
update imgscalr to version 4.2
improve screenshot resource
improve equals, hashCode and toString of plugin information class
added equals, hashCode and toString methods to Plugin class
improve logging of default plugin scanner
added equals, hashCode and toString methods to PluginResources class
fix bug in DefaultFileFilter constructor