Add localization options for messages (such as no PDF viewer)
Add back languages option
Add Japanese translation.
Following upstream
Following upstream 2
Update README with localization instruction
Add simple document for testing LaTeX
Merge pull request #26 from ASMfreaK/master

Russian localization updated
Merge pull request #27 from yoneken/JapaneseTranslation

Add Japanese translation.
Externalize exception message
Add "pref" prefix to preference summary strings
Relocate preference summary messages to strings_activity_settings.xml
update japanese translation
Merge pull request #28 from yoneken/JapaneseTranslation

update japanese translation
Updated russian localization (including shared pref translation)