UI improvements

[zeOrb]

@zafio;310462

Hi! Here is a list of suggestions that I think would improve a bit the UI (let me know if any of this is already possible in any way!)

• Option to hide Transform gizmos:
  Why: Sometimes it gets in the way (some times I’ve translated an object by accident) when trying to select multiple small close objects in perspective view.
  Usability: As simple as pressing the current shortcut again, so if we have Translation active, we press W again or Click on the button to hide/disable it. This would leave us in kind of a selection mode.
  Option: An actual selection mode could be implemented, with its own button and S key as shortcut.

Assign hotkey to “Show transform widget” in Keyboard shortucts

@zafio;310462

• Option to Transform with hotkey axis constrain:
  Why: For me at least, it’s easier and faster to press the hotkeys than to have to acurately click on the gizmo’s axes.
  Usability: For example, W key > Z key > move cursor to translate an object along Z axis > LMB to acept/stop translating.

CTRL+LMB/RMB/LMB+RMB for X, Y and Z movement.