Add parameter to map generator for how to choose point set
Create a helper class that provide point selection algorithms
Add square/hex grid point generators; make them use 0 lloyd iterations
Make Random points and Random+LloydRelaxation into separate types

* This replaces the klunky separate Lloyd Relaxation iterations parameter
Add buttons to choose how points are selected
Add buttons to control number of points

* Map generator previously had number of points as a static; made this a parameter
* Also added "needs more randomness" flag in map generator to add random elevation gains
  * This was needed because hex/square grids are not random, and there wasn't enough randomness anymore
Rename "Export bitmaps" to "Export byte arrays" to avoid confusion
Rearrange the UI sections to make them all fit in the sidebar