add -ggdb compiler options and gitignore

don't keep object files and binaries in git
add -ggdb to the makefiles for all 5 linux cmd line binaries
Merge branch 'master' of https://github.com/tyler123durden/rtklib

Conflicts:
	app/str2str/gcc/makefile

(drop [wr] -ggdb compiler option, we can easily readd it)
resolved merge conflict by re-adding -ggdb compiler option