Ignore Eclipse files.
Update build scripts for Sencha.
We need an additional symbols.js target to list Sencha Cmd compiler
directives for VexFlow classes. Compression of the javascript is also
disabled, for ease of debugging (plus, Sencha Cmd will automatically
add compression when the library is included in a Sencha project).
Use ExtJS for DOM manipulation, rather than jQuery.
Fix error in document formatter detection.
The formatter variable was misnamed, so the default formatter was always
being used, even if a different class was explicitly specified.