Robustness, WinPR, Codecs, CMake

libfreerdp-core:
* fix valgrind warnings
* robustness fixes in GCC, MCS, core RDP

libfreerdp-client:
* improve .rdp file parsing/writing functions
* extend usage of .rdp file options

wfreerdp:
* Vastly improved rdpsnd implementation (now as good as mstsc)
* Improve windows build system options

channels/cliprdr:
* Refactor and offer callback interface (eventual replacement of old eventing system)

libfreerdp-codec:
* Implement RDP6 planar encoder, fully unit tested and compared with mstsc

libfreerdp-crypto:
* Offer new callback to expose X509 certificate directly to client implementation

libwinpr-synch:
* Implement timer queues and timers (not yet ported everywhere)

libwinpr-crypto:
* Initial implementation of CryptProtectMemory

libwinpr-sspi:
* Fix bug in server-side NTLM module (incorrect TargetName length)