RegexEngine

this is a project in my parth to learn Computer language theory of Compilers, the main purpose here is to implement a high performance regex engine which is essential for the scanner.

Support features:

1. Support Alphabet is Ascii characters;
2. Support operations are:
   1. Union;
   2. Concatenation;
   3. Kleene closure.
3. Support char '.' to represent ANY chars;
4. Support Extended Regex standard like:
   1. '?' operator;

Planned features:

1. PERF improve;
2. Log improve;
3. Extended Regex engine including: + and etc