Download gstreamer for OS X travis builds

Fix string replacement

App store icon

# By Gus Grubba
# Via Gus Grubba
* 'master' of https://github.com/dogmaphobic/qgroundcontrol:
  Update README.md

Update README.md

Updated name to make consistent with App Store

Updated name to make consistent with App Store

Obligate LinkInterfaces to implement getLinkConfiguration. …

Ios app store

* Mavlink/master:
  Fix github json download failure argument string

Updated App Store certificate (public) UUID.

Bug noted in #3465

* Mavlink/master:
  Improving coding style
  Updating mavlink v1.0 ref
  Removing AndroidJoystick (requires Qt5.6)
  GPSFact.json: add RTK float & fixed types
  gps: use a read buffer size of 1024
  gps: update drivers submodule
  gps read callback: avoid sleep, don't wait when data already available
  gps: use GPS_RTCM_DATA mavlink message for RTCM, use fragmentation if needed
  gps: update submodule
  gps: use an inline function for usleep instead of #define
  GPSProvider: add SIMULATE_RTCM_OUTPUT to enable simulated RTCM output (currently disabled)
  Sync with official
  Fixing syntax
  Android Joystick support
  Fixing syntax
  Android Joystick support
  Fixing syntax
  Android Joystick support

Messages are in English. If you have the iOS device set to another language, things get spoken all wrong.

Obligate LinkInterfaces to implement getLinkConfiguration. 11ab9aa0 introduced a bug where TCP links would cause a crash loading the sensors page

Joystick restructure

GPS RTK: use GPS_RTCM_DATA mavlink message

Allow arm with no GPS lock

Enable ROI and MOUNT support for PX4

This avoids conflicts with other code

Better handle disabling AP channel number for WiFi parameters.