tiarmclang compiler: modified condition-decision coverage

Get introduced to MC/DC.  Learn how it can expose gaps in both test input and code.  A demonstration is given, based on the earlier video about code coverage basics.  Many steps are the same.  Only the differences required by MC/DC are shown.  The main focus is on explaining the display of MC/DC.  Lots of information is shown in a small space.  It takes time to understand it all.