Adding support for backing up the db
added Skip and GetDataSize introduced by Michael
Merge branch 'voron' of https://github.com/ayende/raven.voron into voron
If storage environment is disposed then dispose all active transactions as well
Fixing AccessViolationException
Cleanup of UnmanagedBits
Merge branch 'voron' into new-free-space-management

Conflicts:
	Voron/StorageEnvironment.cs
Fixing invalid invalid shift operation for pointer (all tests pass now!)
Removing TODOs
If we look for multiple pages we cannot return some from the end and from the begin as a consistent range of pages
Adjusting tests of free space for the current API