COVERAGE! Also fixes prvm always running as PRVMSLOWINTERPRETER :(

COVERAGE! Also fixes prvm always running as PRVMSLOWINTERPRETER :(

Very basic implementation. Needs a persistent store later, I suppose, as
well as better output (e.g. for statements and coverage(), also show
function, file and line).

prvm_coverage 1: report function call coverage
prvm_coverage 2: report coverage() builtin coverage (compiler aided)
prvm_coverage 4: report statement coverage (SLOW)

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@12042 d7cf8633-e32d-0410-b094-e92efae38249