Allow changing hotkey for tool selection toggle (RMB)

[Shiu]

User reports that clicking RMB to toggle last selected tool gives troublesome behavior when holding RMB if the button is unreliable RMB (hardware issue).

Two options:

1. Allow changing the hotkey for toggling last selected tool.
2. Option to disable RMB for toggling last selected tool.

Thread link: http://esotericsoftware.com/forum/Question-How-to-disable-RMB-click-switching-to-last-tool-12946?p=57487#p57487

[TextusGames]

We already can change keyboard hotkey "Last Tool: 'Key'". But that does not disable RMB from switching tools.

So we need an option to disable RMB last tool switching and RMB tool cycling in mesh editor (create, move, delete).

Also. "Last Tool" shortcut does not currently affect tool cycling in mesh editor and for this should be a new short cut or preferably it should be the same "Last Tool" shortcut.

[NathanSweet]

Disabling right click mentioned in #677.

[NathanSweet]

Last Tool in 4.1.07 now toggles the tool in edit mesh mode.