Pseudolocalizer improvements.

Fixes accented pseudolocalization and adds RTL pseudolocale.

This change contains following modifications in the pseudolocalization logic:
1) zz_ZZ pseudolocale was removed;
2) en_XA pseudolocale was added for pseudo-accented;
3) ar_XB pseudolocale was added for pseudo-rtl;
4) Pseudo RTL localization functionality was implemented;
5) Text expansion functionality was implemented;
6) Text bracketing was implemented;
7) Couple of issues of previous implementation were fixed.

Change-Id: I9f7f27bed717e39e82717d15c398decffc8bec3c
Signed-off-by: Anton Krumin <antkrumin@google.com>