Mouseless input

[jhmartin]

While entering many bib reports, it would be useful to not have to remove the hands from the keyboard. One thought is to make the last text entry field have some logic such that I can enter i/o/d and have it treat that the same as clicking the related button (and remove the value). Or, some other way that I can hotkey that -- trackpads are not very accurate and are difficult to use at speed.

[jhmartin]

Even better if it could be done entirely from a 10key; + for in - for out or something like that.

[nojronatron]

Related to #23