update bootstrap 2 to 3

* remove simple_form
* add bootstrap_form
fix change note field column span
fix broken concept mapper markup
add bootstrap styling to concept mapping manager widget
only show loading indicator when uris need to be resolved
add blank notation in edit mode
fix button styling
tweak configuration styles
tweak form action styles throughout
tweak search form styles
add kaminari_bootstrap to support bootstrap 3
fix i18n key
adopt bootstrap 3 list styles
base letter selector on actual label records
rename spinner to indicator

to be concise with namings used throughout entity selector
tweak onebox loading indicator style
wrap autocomplete indicators in input group
remove simple_form remnants
bump bootstrap_form
lock bootstrap_form to ~> 2.1.0