Add java test cases for WA GB18030 Certification.
1. Fix Copyright info
2. Change GB18030CharSet to be constructed using the Unicode UTF-16 codepoints.
fix path in readme file.
Merge pull request #17 from gcheng/readme

fix path in readme file.
Merge pull request #250 from gcheng/dev

Dev
Merge pull request #247 from LucieZhou/master

Add java test cases for WA GB18030 certification.