Build cleanup: Removed what appear to be temporary files and moved ELF2IMG to OUTPUT_DIR
Moved settings.bsp out of the path
Build system fixes

Put version.h in build directory
Fixed out of source build not being completely out-of-source (version.h)
Merge branch 'cleaner_tree' of https://github.com/litghost/bladeRF into litghost-cleaner_tree
fx3: Create elf2img in output dir.