Fix issue running migrations

I was trying to upgrade from v1 to v2 - when I ran the migrations all the editable elements in my pages were deleted. This LOC fixes this issue.
Copy czech translations as slovak translations
Replace cs with sk in slovak translations
Return the original input in translate.rb if no translation found
Raise an exception instead of returning the original input if no translation found
Add Slovak translations
Fix indentation using tabs to spaces in translations
Fix indentation using tabs to spaces in the Slovak translation
Fixed empty fields in content_entry CSV export
change the order of the content asset types + prepare the views to include for instance a search bar
upgrade to Rails 3.2.17
use lvh.me instead of example.com when developing the engine (+ rake task to move sites) + update README.textile
fix issue #869 (PR #902). use force_encoding for all the ruby versions (we dropped ruby 1.8 support already for a long time)
Merge pull request #897 from colibri-software/fix-content_entry-csv

Fixed empty fields in content_entry CSV export
fix issue #895: leading/trailing white space on ICanHandlebarz.js
fix issue #894: undefined confirmation message when deleting theme assets
add missed russian translations
example for issue #890
add a flag for the sk locale + fix a conflict
Merge branch 'pr/885'