drop MicroKernel getNodes(String, String) convenience signature

the MK API provides two getNodes signatures:

• getNodes(String, String)
• getNodes(String, String, int, long, int, String)

the former is a convenience method and equivalent to
getNodes(path, revisionId, 1, 0, -1, null).

it's currently only used in test cases. in order to
streamline the API and the javadoc i suggest to drop it.