submodule update: axl, doxyrest, graco

* axl 57c2320c...cad19f45 (3):
  > [axl_test] add a test to check FPGA-encoded ULEBs
  > [axl_io_hid] fix: incorrect value passed to hidComplete (hid_init, hid_exit, hid_set_nonblocking return 0 on success, -1 on error)
  > [axl] release axl-6.3.0

* doxyrest a94b8d5...7e42f92 (1):
  > [app] push source position error when expat fails to parse a file due to a XML syntax error

* graco 4a3baba...c7d7675 (1):
  > [graco] release 1.4.0