Merge pull request #1 from MuMech/dev

Merging lastest changes into codepoet development branch
Fixed a bug introduced in the recent landing update that caused TerrainAltitude to be called from the simulation thread. Now it is only called from the main thread, which seems to result in less bizzare things happening in the log, and no (less?) visual glitches in the terrain rendering
Merge pull request #273 from codepoetpbowden/dev

Fix for graphical glitches and bizzare behaviour on landing introduced in latest landing update