merged other ODDs into main one. Keeping old ones for reference for now.
added schema
merged with other ODDS, fixed schematron
made most files valid against MEI schematron and against new MEI2VF schema
renamed doc to odd
removed old ODDs
renamed odd and schema
fixed missing xml:id attribute in new common.opt atts class
associated MEI2VF schema
restored ptrref module for meihead support
created readme explaining ODD usage for MEI to VexFlow
Merge pull request #32 from raffazizzi/master

Added ODD specification; associated generated schema with test files.
added basic support for center aligned mRests
added tuplet support in meilib
added meilib to unittest.html, set tests.html to initial state
Merge remote-tracking branch 'upstream/master' into dev