Updating CSS grammar
Updating CSS grammar

Adding rule for 'namespace' and 'charset'.
Adding suport to list-of-media-queries in 'import' rule.
Adding SEMICOLON to tokens.
antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4