Big syntax and roxy overhaul. 

Major mods to get_temp methods, that are more accurate for bottom temp extractions. Haven't tested all cases that were covered by current master of rGLM. These include 0 size .nc files, and dried up lakes etc.

@lawinslow I am going to keep this open until my syntax overhaul is complete. Just wanted to give you a heads up as to what the changes look like. 
The get_temp, get_surface_height, etc are the functions to get those data. The get.lvl just puts it in the weird Lake Analyzer format. I can export those easy enough, just didn't think they were necessary for anything other than formatting in the background.