Customizable Stone Turret v1.3

First OpenScad encounter and I kind a like it.
After downloading this [stone turret](https://www.thingiverse.com/thing:130629) from drxenocide, it was time to play around a little.

So added some new features:
* optional door opening (doorheight, doorwidth)
* circulair wedge brick for door top
* half stone wedges next to the door opening
* optional stair (stairwidthratio)
* crown floor with stones
* crown height (num_top)
* update angled wedge bricks, with overhang angle option (overha