Tab functionality

[submicron13]

I think this extensions is fantastic, and I can't imagine why it's not part of the ms python extension.

One improvement I desired was being able to tab to place holders when it drops the snippets. I removed the builtins because there were so many ( too many to edit ). So I culled the list to the non-built in examples. I added place holders to almost every function.

I think it would be beneficial to others to add the tab functionality.

[ericsia]

@submicron13 it is updated here