Updated math and rand libraries to use double.
Changed namespaces to be all lower, to follow established style, changed sample Duck programs to reflect that. rand.rand() became rand.randint() as rand.rand() seems to cause errors in Duck.
Set CXX env var to specify suitable C++ compiler (travis)
Use CMAKE_(C|CXX)_COMPILER options
Use -fprofile-arcs / -ftest-coverage as compile option for gcov
Add gcov to check test coverages
Use coveralls to check test coverage on web browsers
Merge pull request #15 from rpcope1/master

Updated both libraries to use double instead of float.
Merge pull request #16 from gregtour/test-coverage

Set up for code coverage with coveralls.io
Improved the way error codes are passed through functions.
Increased precision of floatp print/tostring to 16 digits as double type.
Added Stack Trace on program fault and display line number of where program ends.
Also prints the syntax tree production for the failed instruction.