Don't support platforms bundler doesn't know about

This is an alternate solution to #872 that should prevent folks from
running into #876.
Revert back to https for rubygems source (oops!)
Bring Gemfile.lock up to date
upgrade some gems, keep clockwork at 0.7.0
Fixing #851 - removing icecube and reccuring_select references from main Gemfile and minimizing default plugins to avoid unexpected dependencies during runtime
For users without both postgres and mysql installed, be a little more intelligent about the related gems
Moved configuration to Concerto admin settings
Revert "For users without both postgres and mysql installed, be a little more intelligent about the related gems"

This reverts commit ce80cf45d71c52158867abde58ff597309ea62d6.
Revert "Revert "For users without both postgres and mysql installed, be a little more intelligent about the related gems""

This reverts commit fcd64dc63cfd60b4c143c6ad4855d25a3ef09037.
Revert "Moved configuration to Concerto admin settings"

This reverts commit 2555f4fc752228df1530bab780da540e56c2eb06.
#879 write contents to file using correct attribute
Use fork of docsplit until pull request is merged to allow IM/GM and current libreoffice compatibility
Lock datepicker version and change docsplit branch
closes #880 converted document preview
remove 'see log' phrase
Remove jquery-timepicker-rails and close #885
Merge branch 'master' of github.com:concerto/concerto

* 'master' of github.com:concerto/concerto:
  remove 'see log' phrase
  closes #880 converted document preview
Reverting cf1df9c7ceb31600c286e5880e3eb5d1b842daf1
close #885 update timepicker and specify new location of datepair
fix #882 if preview exists it should be the only media record