CB-6344: Specify after which sibling to add config-changes in plugin.xml

* refactor munges - now they are in a more extensible form (munge.files[file].parents[parent][index] { xml, count, after })
* add an after parameter to graftXML which contains a list of possible predecessor elements separated by semicolon
* fix unit tests and add new ones

github: close #68
CB-6272 Fix subdir bug + tests & meta fetch with a src directory

github: close #66