MCJIT changes: impalad tests to pass

Added resetPermissions() method for MemoryManager, recomipling MCJIT module
on every function add, not aborting when can't resolve extern dependecies
Refactoring.

'resetPermissions' method default implemtation added to JITMemoryManager.
TrivialMemoryManager class modifications: added resetPermissions method.
Resolving pnacl undefined references.
ZMemoryManager added. It's suited for 64K code alignment.

Needed by ZeroVM jail/unjail system calls.
Tests for ZMemoryManager added.
Merge branch 'github/pnacl'
ZMemoryManager changed.

Implemented apply/resetPermissions methods, modified allocation required size calculation.
Refactoring.

Remove FreeSpaceStart variable.
ZMemoryManager tests updated.
Merge branch 'pnacl'