Merge pull request #1 from arjank/master

Fixes incorrect handling of nested global close tag
Merge pull request #2 from arjank/master

Fixes newly introduced bug with incorrect handling of nested tags
Fixed bug in which the quoted version of a smiley became an internal [smile] tag.
Merge branch 'master' of github.com:devize/sml-parser
Put some whitespace around the quoted version of a quote.
Makes lexer case insensitive

The lexer is now case insensitive; it converts all tags to lower case as it processes them.
Includes tests to check the behaviour and some test code cleanup.