Tajik Translation Updated

Tajik Translation Updated
Merge pull request #361 from Ibragimov/master

Tajik Translation Updated
A little improvement in plain text converting for RTL languages
Refactor work with RTL languages in word search list and history list
Properly handle non-normalized unicode headwords

With that change users should be able to search headwords in
any form. For example:

U+03B5 GREEK SMALL LETTER EPSILON and U+0301 COMBINING ACUTE ACCENT

is considered equal to

U+03AD GREEK SMALL LETTER EPSILON WITH TONOS

And no matter in what form the headword is provided in the dictionary, users will be able to find it,
even using the different form.