Some improvements of String
Fixed CPU endian detection
Fix UTF-16 decoding where wchar_t is not 16-bit
Fix UTF-16 BOM detection
Avoid creating new String object when comparing
Use the standard library to convert between UTF-8 and UTF-16 where possible
Revert "Use the standard library to convert between UTF-8 and UTF-16 where possible"

This reverts commit 19ce4d0dfa8c13255f56342f8c179c6a601d9b2d.
Use the standard library to convert between UTF-8 and UTF-16 where possible
Removed null termination from return value of String::data()
Merge pull request #103 from TsudaKageyu/string-improvement

Some improvements of String