patch applied (ghc): parseInteger-> parseUnsignedInteger to clarify meaning

[Isaac Dupree]

Sat May 26 14:22:04 PDT 2007  Isaac Dupree <id at isaac.cedarswampstudios.org>
  * parseInteger->parseUnsignedInteger to clarify meaning
  I decided against adding parseSignedInteger since octal
  and hex literals often have junk between the '-' and the
  digits, but, compare to Util.readRational which does handle
  signed numbers.  Also since Integers - mathematically and
  in Haskell - can be negative, normally.

    M ./compiler/cmm/CmmLex.x r1
    M ./compiler/parser/Lexer.x r1
    M ./compiler/utils/StringBuffer.lhs r1