Main: Whitespace (including tabs!) and svn:keywords cleanups by scm.

Main/Machine+Session: New generic client session watcher implementation based on token objects, works on all platforms and is used for now on XPCOM. Additionally a better error message when several API clients are racing for a lock, previously it could be quite confusing.

Main/Medium: redesign API level medium locking, needed conversions from MediaList to MediumLockLists in several places, forced cleanups elsewhere, too Main/Token: introduced token objects for controlling the unlocking, will be used as a general concept in the future Main/Snapshot: snapshot deletion needed significant cleanups as it was still using many shortcuts, directly calling the API to lock media instead of using lock lists. Now much better, and the online snapshot deletion is also a lot cleaner as it no longer passes unnecessary parameters around which are already known in the machine/snapshot code Main/MediumLock: small improvements, now has a mode which skips locking already locked media, needed by the Snapshot code where we have overlapping lock lists and have to update the original one instead Main/Console+Session+Machine: follow-up changes for the online snapshot merging parameter passing simplification, plus an unrelated lock order violation fix in Machine which happens only for inaccessible machines Main/testcase: update correspondingly doc: update SDK reference