caching by rack-cache
add spring and quiet_assets gems
remove temporary files for generating gif animation
specify recording time by float
store gif times in float
consider reaction delay of human
Merge branch 'feature/gif-no-roundup-time' into develop
Merge pull request #21 from shouichi/feature/dev-improve

add spring and quiet_assets gems
Merge branch 'feature/caching' of https://github.com/shouichi/tv-broadcast into shouichi-feature/caching

Conflicts:
	Gemfile.lock
fix bug: font-awesome icons are 404 in production