libgphoto2 2.5.11 release

canon:
* not experimental anymore, for some years
* some bugfixes in configuration handling

ptp2:
* canon: EOS capture improvements, also supporting new EOS
* sony: tethering and trigger capture implemented, capture stability improvements
* sony: exposure compensation setting fixed
* sony: capture and autofocus configurations, similar to eosremoterelease
* generic: fixed serialnumber retrieval
* nikon: "autofocus" config variable for global autofocus enable/disable (default on, default liveview off)
* various bugs fixed, stability improved
* ptpip: allow different event ports. --port ptpip:IP:dataport:eventport
* New ids reported:
  - Sony Alpha 7, DSC-RX100M4, NEX-7, DSC-HX20V, Alpha 6300, A7S II, A7,
  - Nikon DSC Df, D7200, D5, D810A, 1 V3
  - Canon EOS 1Dx Mark 3, 80D, 5D Mark IV
  - Canon Digital IXUS 180
  - various music players / android phones imported from libmtp

libgphoto2:
* Speed up initial startup.
* Win32: store settings in the "User Profile\.gphoto\settings" and not in C:\\Windows anymore.
* gp_widget_changed() no longer clears the "changed" state to make this API more consistent.
  Use gp_widget_set_changed(widget,FALSE) to do so.

examples:
* sample-photobooth: a sample program handling tethering, SIGUSR1 driven capture and SIGUSR2
  based configuration reading.
* sample-afl: code to inject afl fuzzing data

translations:
* updated swedish, ukrainian, polish, finnish, russian, danish, polish, brazilian, serbian, dutch, chinese