This commit contains work done by Eurecom and by Benetel.

remove RRC_VERSION macros, simplify build-oai and CMakefile.txt accordingly, get rid of remaining compilation warnings (opt module improperly merged and patch asn1c files with tests against max 64 bits integer value)

Remove warnings popping up on:
    ./build_oai --eNB -w USRP

Maybe not always the best solution.

UE directory splits, creation of UE-specific files, common UE/eNB files and extraction of UE/common components from eNodeB files. renaming of files to minimize common names across directories (i.e. defs.h, vars.h, extern.h)