mrp: msrp, in various msrp_emit_xxxx() functions set tx flag to zero

Previous code would not set an attributes tx flag to zero. Although strangely,
if additional attributes were added due to first value incrementing, thoseh
attributes did have their tx flag cleared. Code probably masked this issue by
only starting a join timer upon request.
mrp: msrp, in mrsp_emit_xxxx() correct exit condition when approaching msg_eof
mrp: msrp, add more CppUTests
mrp: replace 'magic number' usage of minus 2 in mrpdu_msg_eof compare with MRPDU_ENDMARK_SZ
mrp: add database reset functions to mmrp and mvrp
mrp: cpputests, remove unused in msrp_tests
mrp: cpputests, add mmrp and mvrp tests
mrp: cpputest, add applicant FSM test shell
mrp: cpputest: cmake file GLOB update to use all *.cpp files in dir
mrp: cpputest: add tests for issue#99 for mmrp and mvrp. No functional changes.

This commit also contains small updates to emit vector functions in mmrp.c and mvrp.c.
The change updates ordering of when the .tx flag is reset to more closely
match that in msrp.c. The change will not affect operation at all.
mrp: mmrp/msrp/mvrp correct xxxx_emit_XXXvectors() correct while() attrib msg space test - issue#100
mrp: msrp: whitespace cleanup
mrp: mmrp.c, get rid of a magic number
Merge pull request #103 from audioscience/cpputest

correct .tx flag handling and while(room) conditional in emit vector functions