Fixed missing Japanese characters in the OSK.

Also added the vowel lengthening character to Katakana and Hirigana
Fixed incorrect る/ル misplacements in the Japanese Hirigana/Katakana characters. Replaced them with the appropriate ろ/ロ character.

Fixes issue 2468.
Merge pull request #2472 from lioncash/master

Fixed missing Japanese characters in the OSK.  Fixes issue 2386 and issue 2468