Merge remote-tracking branch 'origin/lua_experiment' into all_merged_with_lua

* origin/lua_experiment: (96 commits)
  cocoa_common: handle keyboard modifiers for mouse events
  osc: Large parts rewritten, now 5 times faster!
  input: Ignore spurious mouse moves
  configure: Add some -Wno-error= flags to ERRORFLAGS
  osc: use new defaults.lua features and other minor stuff
  defaults.lua: add function round_rect_cw() and merge()
  osc: Modified Proportions and other stuff
  minimal event infrastructure
  osc: Minor modifications
  resolve forgotten conflict in cocoa code
  osc: cleanups
  kill ratio-pos property
  osc: no idea
  osc: fix incorrect scaling of mouse area
  osc: add display of track counts
  lua: export track list
  manpage: document input sections
  command: add commands to enable/disable input sections
  input: store number of binds instead of 0 termination
  input: keep number of keys, instead of using 0-termination
  ...
Merge branch 'lua_experiment' into all_merged_with_lua

* lua_experiment:
  mp_lua: fix compilation with libav