Cleaned up tools/platforms/msp430/cppbsl

`tools/platforms/msp430/cppbsl` had lots of committed Makefiles and the like, as well as its own bootstrap/configure setup. I merged this into the main tinyos-tools automake build process and removed the autogenerated Makefiles. cppbsl also needs a library (libpopt) I didn't have on my system and rather than add another dependency to tinyos-tools, cppbsl will only install if the user already has libpopt.