Partly fixing MID-1969 - fixed losing namespaces in some paths/qnames. (Work in progress.)

Changed QueryConvertor to include "preliminary parsing" mode in which most XNodes are parsed without actually constructing ObjectQuery. This is invoked when parsing the source file, to eliminate unparsed XNodes as much as possible.
Also, simplifying SearchFilterType by eliminating DOM version of the filter clause.
Merge branch 'master' of https://github.com/Evolveum/midpoint
Resolving MID-1969 (#3 and partly #1). MID-1970 (#1). Making XMLNS-less imports really work.

Made equals() in ItemPath/ItemPathType/NameItemPathSegment stricter w.r.t. schemaless items. Introduced equivalent() method to these types as an substitution for previous equals() behavior.
Changed XMLNS handling when serializing objects. Repetitive genXXX declarations are now mostly avoided.
Preliminary parsing of search filters (MID-1970/#1).
Changing schema for bulk actions to avoid name clash (c:expression/s:expression). Fixing PrismBeanConverter to work correctly with changed schema.
Made all caches in PrismBeanInspector synchronized (caused lockup when running multithreaded tests).
Changed parsing/schema registry to really implement XMLNS-less imports.
Merge branch 'master' of https://github.com/Evolveum/midpoint