RepositoryHelper relativizePath, appendPath: changes for relative paths

relativizePath: +assumeCommon option to work with abstract relative paths
appendPath: don't normalize results
start of changes for packager stuff

mostly just broken at this point, api still being worked out
minor changes

PluginsAnalyzer ctors, repository file deprecations, indent, import
fix after api changes
remove kettle from dependencies (cpk legacy dep)
PluginIOUtils needn't be a singleton
corePlugin: deprecations, evil autodoc
assorted jdocs