Support unicode identifier

Refer #211 

I hope to support unicode identifier (non-ascii identifier) in Golo too.

Why?  I'm Japanese, so I speak and write Japanese everyday.  Sure I use no Japanese in program usual, but in the case of writing test code, I often use Japanese for test case name.  Because, that is better way for telling summary of test case to Japanese.

In addtion to, Java has been supporting unicode identifier.  If the method were named in unicode, Golo can't call this method. It is very problem!

Thus, Golo MUST support unicode identifier.
Ｉｔ means
  - \`constant' in Japanese (Hiragana)
  - \`variable' in Japanese (Katakana),
  - \`function' in Japanese (Kanji),
  - \`argument' in Hangul,
  - \`structure' in Russian,
  - \`element' in Arabic

I use Google Translation :cold_sweat: