This reverts commit 4568adb4.

 * ignore .tx folder
 * cmake: when UPDATE_TRANSLATIONS=ON, extract new strings only to the
english translation file.
 * added info in CONTRIBUTING.md
 * updated english translations

Consistency for certain affixes

Added new strings for Cockatrice
New Oracle translation
Cleaned up vanished strings

Translations have been updated.

Added new strings
Changed all instances of ‘zone’ based on oracle text of Torrent
Elemental
Changed all instances of ‘registered users’ into more commonly used term

cleaned up vanished transitions in the mean time.

Added translation of some new strings and svg file of South Korean flag.

Flag of South Korea is from
http://commons.wikimedia.org/wiki/File:Flag_of_South_Korea.svg

Fixed a non-standard word (손패) into the word that is used in official
translation (손)

Added line breaks in Korean translation for better readability.

Edited several sentences after a third-party review