add overload battleground effect
Preliminary custom cards
Implemented a custom cards parser in Boost::Spirit
Fully fleshing out skills and symbol tables

Updating docs, added template
Code cleanup & refactoring
Fix angle brackets in README
Fix a comment
Parse failures exits with error instead of uncaught exception
ALL not supported. Removed upper case example.
joined overload and new custom_card feature
Abort execution for -o=[card_id] if card_id does not exist

Fixes #52.
Version 3.5.0
Merge branch 'release' of git://github.com/zachanassian/tu_optimize into release