Bugfixes in CssTokenizer: '.' was parsed as a number and '-'
wasn't properly handled by readIdent() causing '10-1' to be parsed as
'10-' & '1'.

CssTokenizer no longer parses Token::FUNCTION tokens. It is now up to
ValueProcessor to reckognize '{identifier}(' as a function.
Parentheses that don't contain a statement that ValueProcessor can
process are now ignored rather than causing an error.
Updated CssTokenizer_test to not test for function tokens.
Updated CssTokenizer_test to not test for function tokens.
Updated LessParser so parameter rulesets don't go through the
ValueProcessor when they are declared.
Updated ValueProcessor so it can still handle parentheses even if they
don't contain a statement.
Updated tests.