Setting object position is propagated to the physics simulation even for dynmamic objects.

The velocity is also reset to 0, which makes sense after forcing a dynamic object position.
Known issues:
- in interactive mode, changing an object position by rna causes a simulation step
- setting any part of the object position or orientation causes the full matrix to be applied to physics => missing true rigid body API

Interactive mode: new scene.flag SCE_INTERACTIVE to update the depsgraph without frame change but running physics.

Interactive button added on time line.

Fix bug with transformed object interfering with rigid body simulation.

Note: bug was caused by use of legacy ob->flag & SELECT. New OB_PHYS_MOVING
flag to mark that an active object is being transformed.

Make active object position update independent of cache write in preparation
of interactive physics.

BGE: bge.render.offScreenCreate() takes one more parameter, reflect this in the argument format string.

BGE: Fix silly typo that invalidates negative scaling camera feature.

Negative scale on camera is a nice trick to invert render image on one
axis at no extra CPU cost. It was implemented in the Decklink branch but
I introduced a typo when porting it to master. It is now fixed.

Fix BKE_nurb_handle_calc_smooth: no clamp 'HD_AUTO' handles.

Implement smarth algorithm to compute automatically the bezier handle that
produce no acceleration discontinuities in a series of auto handle points.
The result trajectory is physically as 'smooth' as possible given a set
of fixed point and a start and end location and velocity.
See BKE_nurb_handle_calc_smooth()

Fix clamping of auto handle in some rare case.

BGE: Fix 1-pixel bug with viewport and aspect ratio.

The canvas viewport is initially set as (0,0,width,height) but treated at
OGL level as (left,bottom,right,top), which differs by 1 pixel.
This was causing a wrong aspect ratio in the render.

BGE: new bge.logic.Render() to perform render w/o logic step.

This function works only if python has control:
1. add scene custom property, call it __main__
2. give it string value as the name of a text block
3. code game loop in python in text block. Example:

import bge

bge.logic.setUseExternalClock(True)
t = 0.0;
scene = bge.logic.getCurrentScene()
cam = scene.cameras["Camera"]
cam.setViewport(120,120,370,370)
while not bge.logic.NextFrame():
cam.useViewport = True
# second render with viewport enable, clock time unchanged
bge.logic.Render()
# advance animation for next frame
t += 0.02
bge.logic.setClockTime(t)
cam.useViewport = False