Added cryptsy and the ability to do trade-percentage in the config file.

Added in two features: 

1.  Cryptsy support.  It's not the prettiest (as I'm not a great NodeJS guy), but it seems to work in my testing.  I also didn't add in all of the various markets or their minimum values.

2. tradePercentage: I wanted to have the ability to say "please don't trade away everything" in the config file.  That now calculates in the portfolio manager before a trade is executed.