Add FastTracked osal PRs

nasa/osal#890 - Fix #875 - move copyblock size to a #define and add comments
nasa/osal#891 - Fix #873 - removed rogue while loop
nasa/osal#892 - Fix #868 - scripted replacement for #include <os and #include <OSC_ matches of < and > with "
nasa/osal#893 - Fix #859 - consolidates the duplicated switch in OS_SocketOpen_Impl
nasa/osal#894 - Fix #854 - Const correct input pointers
nasa/osal#895 - Fix #851 - removed network prototypes defined in osapi_sockets.h that are also in osapi_network.h
nasa/osal#896 - Fix #842 - removes NULL redefine from common_types.h
nasa/osal#912 - Fix #911 - Add Contributing Guide