[v0.2.6] 한국어, 日本語, 中文(SC, TC) and кириллица

[New Features]

• Now you can write 한국어, 日本語, 中文(SC, TC) and кириллица in your contents.
• Each fonts are accessible, when you select a corresponding language in the menu.
• Now Japanese(thanks to routehachi@github) and Korean UI is available.

[Improvements]

• Font handling structure is now more robust.(may not noticeable in the program)