Debugging

Hey Adam,

Added  a '-d'/'--debug' option to build with debug symbols and if the command is test to invoke lldb/gdb on the tests executable. I'd like to have it auto set a break point on whatever 'greatest' function gets called on failure, but I tried it on 'greatest_do_fail' and it didn't work,  and lldb can't seem to read 'run' from a file anyway so that will have to wait.