Rename all files, removing the "jquery.ui." prefix;

- By executing https://gist.github.com/jzaefferer/893fcf70b7eebc1dc271;
Rename all files, removing the "jquery.ui." prefix;

- Update all UMD wrappers accordingly;
Minor indentation fix
Tests: Updating file names of CSS imports
Demos: Copy UMD versions of i18n files to datepicker demos