Fixes to voxel node coloration bug

In implementing animation I discovered a bug where sometimes we were getting colored voxels when we don't want them. The problem was related to VoxelNode's constructor not properly initializing it's color member variables.

Some other small changes in this push, related to finding and fixing this issue:

- Shortcut key added to interface "Log" menu
- Coding standard cleanups in VoxelTree
- Proper setting and averaging of colors in VoxelTree
- changing voxel-server's tree to NOT reaverage colors
- change to voxel-server to not always rebroadcast Z commands