Added new input type - tokens

Added a new input type - tokens into SF. This input type can
be used wherever multiple values are allowed.
Also, changed structure of select2 files by introducing a new base
class that has some basic properties which can be inherited and extended
by combobox and tokens.
Added accent-folding functionality for characters with accent - it doesn’t
matter whether users search for cafe, café or even çåFé; the results will
be the same.

Change-Id: I51f2029e0f70f4aa1d99faadb9fd27b334e6ea3d
Merge "Added new input type - tokens"