Missing words in README.md

[kaparoo]

It seems there are some missing words in the README.md.

For example, in "MuNG format and Alignment" section, there are some strange sentences like "The xml:id of the is the unique identifier for the given notehead within the entire MSMD dataset." and "The , , and elements denote its bounding box.". Some nouns must be placed in the sentences.

I'd be grateful if you fill those words to help my understanding.
Thank you!