Docs: updated README.md to reflect linux package build process and dependancy requirements.
Graphing: Fix #481 string modes in logs not being properly recognized
Stylesheets: Fix outdoor style error that was preventing buttons from showing correctly
Stylesheets: Fix #484, dock widget detach/close icons were broken due toduplicate entry in the stylesheet
Comms: Disabled LinkManagers link timeout detection
Map Toolbar: Add horizontal layout to fix button overlapping issue
Battery Monitor: Add preset for Pixhawk/Power Module HV
Actions Widget: Quick fix to make text readable. 

- Proper fix requires the Actions widget to be completely relaid out.
configuration: update version to object to 2.0.15-rc3