FreeRDP, WinPR Various New Modules & Stubs

Server-side channels partial implementation & refactoring:
* Clipboard Redirection
* Drive Redirection
* Sound Redirection

iOS initial sound support contribution

Started new WinPR modules:
* winpr-nt
* winpr-com
* winpr-wtsapi

Vendor extensibility: add extensible build system hooks for vendors without polluting the open source repository.

Mac OS X: Fix building for a minimum version of 10.6

WinPR Utils:
Started new extensible logger (WLog)

libfreerdp-codec:
Make use of partitioned buffer for RemoteFX encoding/decoding.