Add option to run without opening the MATLAB editor

I use this as part of a pre-commit git hook and also sometimes in large batches of files, so it would be nice to have the option of passing in a filename and have the formatter run without opening the editor for performance reasons. A couple of possibilities for the calling syntax:

An optional parameter:
`MBeautify.formatFile('someFile.m', 'someFile.m', 'UseEditor', false);`

An optional positional argument:
`MBeautify.formatFile('someFile.m', 'someFile.m', '--no-editor');`

A new method:
`MBeautify.formatFileSilently('someFile.m', 'someFile.m');`