New Math24 Syntax

Update app to use new Math24 syntax. Also:

*Add specs for Math24Controller
*Change rspec output to use documentation format
*Update gems and add some groupings to Gemfile
*Delete unused lib and bin files
*Add logging files to .gitignore
*Delete old gem and gemspec files (brought over in extraction from Math24 gem)
*Delete old test files for gem
*Delete unused controller action 'post /problem'
*Delete lots of comments
*Remove dependency on Math24 last_answer instance variable
*Fix some whitespace errors
*Delete capture_stdout method from spec_helper
*Other minor refactoring