add gems

 * thor
 * rspec and guard-rspec
prepare rspec

 * add fixture_helper
added notification to tmux display message
:put_litter_in_its_place:
add IOHelper
fix version of ruby
add Object#boolean?
add String#width
add simplecov
include module to class
add StringExtension#mb_ljust
implove performance
add StringExtension#mb_limit
refactoring
remove simplecov
add Table
Merge branch 'develop'