Update/cleanup Makefiles (#265)

- add new target "make mfkey" to build mfkey32 and mfkey64
- include above when "make all"
- fix Qt detection for Kali Linux
- create and use dependency files when building client
- create client/lualibs/usb_cmd.lua from include/usb_cmd.h when building client
- add Windows *.exe files with "make tarbin"
- For the time being don't include Makefile.common in Makefile and client/Makefile
- set com3 as default flashing port for Windows (including mingw)
- remove static targets snooper and cli. Remove their sources as well.