Log replay: Fix for crash when loading tlogs, and another when tlogs stop playing
Control Widget: rename member variables (code review)
configuration: add a default directory for missions (flight plans)
Mission Widget: fix waypoint save dilaog not appearing
Firmware Loader: Fix for px4 PID misdetection
configuration: update to RC6
ComboBox Control: Fixes #522 combobox and layouts effected
Graph View: Fixes #521 Segmentation Fault

Fixes de-reference of NULL pointer and logs issue.
Action Widget: Fixes to layout to move mode drop down
Log Download: Additions to logging to improve debugging
configuration: update to 2.0.15 stable
Updated README.md with SDL2 library
ComboBox: Add ‘down-arrow’
configuration: update to JSON object
Mission Widget: Fix layout issues with mission editing
Mission Widget: Add Default Alt & WP Radius
Mission Widget: Wire up WPNAV_RADIUS setting
Radio Calibration: Protect for array out-of-bounds error
UAS Object: cleanup and addition of MissionOverview object
Actions Widget: Add Preflight Calibration Dialog