Fixed caching and improved logging

* SVNURL.getPath() is the part after protocol, domain, and port. Use toString()
  instead.
* Add logging in case the cache does not contain the required entry, printing
  all keys in the cache so far.
Further cache optimization
Merge branch 'cache-fixes' of https://github.com/daniel-beck/subversion-plugin into cache-fixes
Merge branch 'master' into cache-fixes

Conflicts:
	src/main/java/hudson/scm/SubversionRepositoryStatus.java
Delay activity check
Merge pull request #60 from daniel-beck/cache-fixes

Post-commit hook cache fixes