Release 0.12.0

New features:

• #293 mavsys, mavcmd now may --wait until connection establish
• #293 connection status exposed in mavros/State
• #292 distance_sensor plugin (extras)
• #309 vibration plugin
• #277 gcs link diagnostics on external bride
• #129 FTP FUSE driver

Fixes:

• #300 APM and PX4 version report
• #276 param rerequests
• #269 link diagnostics

Changes:

• FRAME CONVERSION please check that your system still works correctly!
• #266 some period parameters replaced by rate. Old param deprecated, but still supported.