add `bootstrap-timepicker-rails` gem
add bootstrap-timepicker-rails needs js and css require code
used bootstrap-timepicker to show time
add some test code with verify the modified
delete four parameter in class CompoundDatetime, because they are no used
tweak datapicker and timepicker config
tweak datapicker and timepicker style for small screens
Merge branch 'used_bootstrap_timepicker_rails'

fixed #274, closes #283

Conflicts:
	Gemfile