Added lexer_common.rb and start refactoring lexer to use fewer machine instantiations

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extra : amend_source : 22915e8e63f30f97c69ab5a5875f9df9ead13c16
Refactor out another machine instantiation in favor of in-machine actions

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extra : amend_source : 5b35c1db9be61151d6c0d3193836985e8754a4d5
Add basic racc file