improve(Tokenizer) : begin improving Tokenizer
chore (modules) : refine modules and packages (refs #5)
test(Tokenizer) : add test routine for tokenizers (Regex based) (refs #2)
improve(Tokenizer) : add an initial version of LexTokenizer (refs #2)
improv(tokenizer) : improve performance of Tokenizer using JFlex (refs #2)
chore : delete unnecessary files
improve(Tokenizer) : refine kolexer.jflex (refs #2)
improve(Tokenizer) : add regular expressions for symbols and letters (refs #2)
improve(Tokenizer) : add LexerTokenizer and generator (refs #2)
improve(Tokenizer) : add thing routine to korlexer.jflex (refs #2)
improve(Tokenizer) : add LexerTokenizer (refs #2)

Refactor package structure => remove kr.ac.snu
Set default Tokenizer as LexerTokenizer, move other Tokenizers to test dir
Tokenization time was reduced about 23%.
In case of sample docs,
  - by spaces : 5.7s
  - by lexer  : 6.1s
  - by regex  : 7.9s.