BUG, Parse Mulitpart does not properly handle non-file sections with values that have newlines

Here is the fix: http://github.com/nrstott/jack/commit/18e73ba3e5fc976bc3252978395783a6bc89e2f0

I also greatly simplified the algorithm while I was at it.

This bug would occur when you had a text area with 
"line
break"
in it.  The parse multipart would set the value to be just "line"
