Updated the config parser

Updated the config parser to provide better readability and flexibility
in config files. The latest features introduced a really messy way to
handle config files and this update alleviates this by adding the
ability to create profiles and associate them to pools.

Example config file: http://pastebin.com/XXY2u5HT

Todo: Update the config file writer, in-program options and continue to
break off the config/command line parsing code out of sgminer.c
to reduce clutter.