1. Fix stream leak in rdpgfx
2. Make src data const in zgfx. Harden zgfx to be independent to byte order
3. Fix written bytes return value in channel write
4. Add check for return value in shadow_client.c
5. Add gfx callback to send surface command with frame marker pdu.
6. Check remain length for recv subroutine
7. Fix compile errors
This patch contains:
* checks for malloc return value + treat callers;
* modified malloc() + ZeroMemory() to calloc();
* misc fixes of micro errors seen during the code audit:
** some invalid checks in gcc.c, also there were some possible
integer overflow. This is interesting because at the end the data are parsed
and freed directly, so it's a vulnerability in some kind of dead code (at least
useless);
** fixed usage of GetComputerNameExA with just one call, when 2 were used
in misc places. According to MSDN GetComputerNameA() is supposed to return
an error when called with NULL;
** there were a bug in the command line parsing of shadow;
** in freerdp_dynamic_channel_collection_add() the size of array was multiplied
by 4 instead of 2 on resize
