regex used by lexer should be bootstraped

[pfmiles]

the initial version of dropincc.java uses java built-in regex implementation to do lexing. but it does not support named capturing groups and 'longest match among groups' feature, it should be bootstraped after initial version of dropincc.java released.

[pfmiles]

'Longest match among groups' means choose the longest matching from the groups matched at the same time, when matched the same length of lexeme among multiple groups, choose the earlier defined one.

[pfmiles]

0.3.0