[PATCH] Pull Lexer's CharInfo table out for general use throughout Clang

[Joerg Sonnenberger]

  isASCII: Please explicitly check for 0..127 as value range, in case anyone ever tries this on platforms with CHAR_BIT > 8.

  Does it make sense for isIdentifierHead to just use two different masks?

  isHexDigit should be a bitmask too.

  Tests should IMO be != 0, not using ? true : false.

http://llvm-reviews.chandlerc.com/D363