Use buttons not inputs

* Buttons have the correct height in Firefox when using bootstrap 3
Add margin to edit mapping tabs

* The tabs were too close to the top of the new form after the default
vertical spacing on forms was changed
Reduce default right margin

* Gutter widths are bigger now, and a spacing of 15px is too large
between buttons, reduce to 10px again.
Improve edit multiple modal layout

* Remove spurious extra spacing
* Demarcate footer region of modal again