Improved FIT file parsing.

- Improved elevation handling

Improved GPX parsing

- Improved GPX parsing

A few minor tweaks and some housekeeping

- Improved FIT file parsing, - Fix for potential crash new duplicating a route.

Improved TCX parsing

- Support for parsing more GPX extensions - Housekeeping

- Fixes for table header context menu - Housekeeping

- Fix for bug when deleting points - Smaller footprint on disk - Housekeeping

- Improved window title bar - Housekeeping

- Append routes - Clear lap information - Fix for potential crash in as-of-yet-unsaved routes - Housekeeping

- Improved date parsing in TCX & GPX files - Improved feedback prompt - Graph view removed if route has no properties to display - Fix for crash when opening info popover for untitled documents - Housekeeping

- Don't modify map viewframe after deleting points - Fix for potential crasher in TCX files with power data but no timestamps - Housekeeping

- Delete points from the middle of GPX routes - Housekeeping

- Export OSM data - Improved handling of moving time in graph view - Housekeeping

- Fix for potential crash when viewing some routes - Initial support of OSM route format

- Improvements to deleting points / cropping routes - Housekeeping

- Improved path drawing in graph view - FIT export - Housekeeping

- More dark mode fixes - Improved graph path & axis drawing - Potential crash fixes - Housekeeping

- Dark mode fixes - Housekeeping

- Power is parsed from GPX files - Graph path icons displayed in appropriate colour - Housekeeping

- Calories from FIT + TCX files - Normalized power calculation - More fixes for potential crashes - Housekeeping

- Fix for crash when deleting points at end of route - Housekeeping

- Validate "Show POI" in graph context menu - Gear icon & context menu in popover - ZWO file support - Housekeeping