[gcs] specify max map zoom level with -maps_zoom option
- defaults to 18, max is 22
  - TODO: check that a valid zoomlevel was given
  - add it to the menu to change at runtime?
- if available, larger (low zoomlevel) tiles in cache are loaded right away,
  even if higher zoomlevel maps could be downloaded.
[ocaml][tools] don't use custom runtime for ocaml, instead load shared libraries in ocamlrun
since the ivy-ocaml lib currently can't be found with ocamlfind and libpprz is not installed system-wide,
specify the paths directly with -dllpath
verbose option for building ocaml lib
[makefile] cleaning makefiles from -custom param for ocaml
[makefile] most of the ocaml tools are compiling with shared lib

some issues with mixed static/shared lib
[makefile] more makefile cleaning and dynamic loading
[makefile] silence clean target and add missing Makefile
[makefile] fix multimon makefile
[makefile] multimon dll path
[makefile] seems to work fine now
[makefile] deduplication in mutimon makefile
[makefile] make joystick compile on 64bit
[makefile] minor fixes/cleanup for joystick
[makefile] finaly make tools independant of ivy package
[makefile] fPIC for sim...
[makefile] improvements to ocaml lib building
- quiet building of glade stuff
- remove some temporary glade files
[makefile] fix realtime plotter: link glibivy instead of ivy in logalizer
[makefile] use pprzlib has a proper ocaml package
[spi][stm32] updated handling of different transaction lengths
- now tx buffer sizes are independent of rx buffer sizes
- uses a second dummy dma transmit transfer triggered of the
  first transmit dma ISR when 0 < tx_len < rx_len
[spi][stm32] Added second dummy buffer dma handling for rx too
- handled in the same way as tx
- simplifies completion interrupt timing, clearing registers and
  running callback and deselecting slave at the right time,
  AFTER the last byte is fully transmitted.
- Also updated comments.