Compile 'to the top' (i.e. all the way up to RAT_main).

[arwelHughes]

• Remove compile folders for 'DE_compile', 'DRAM_compile' and 'simplex compile' (only used for debugging).
• Modify buildscript to compile both RAT_main and reflectivity_calculation.
• Include RAT_main_mex in the nightly build distributions..