prevent read in freed memory
codec/nsc: initialize elements with NULL

bmpdata and plane_buf[i] are checked agains NULL before using/freeing them
but they were not initialized to NULL. This caused segfaults in
the sample server.
Merge pull request #921 from bmiklautz/nsc_mem

codec/nsc: initialize elements with NULL
Merge pull request #920 from dlesaffre/master

serial port comm: prevent read in freed memory
Merge pull request #922 from awakecoding/master

Platform-Specific System Information
winpr/pool: zero thread pool on creation
Merge pull request #926 from bmiklautz/zero_tp

winpr/pool: zero thread pool on creation