reworked filehandler and associated tests; passed testing
removed a few redundancies in fil ehandler and retested
also updated description
added TextSplitter class, reworked FileHandler to use it, and began adding it to Message.  Retested FileHandler; no spec for TextSplitter yet
simplified message, set it up so that single segment object has all lines; haven't fixed Segment or rspec yet
better filehandler test