Give precedence to feature style
Distinct style function types
Add option to process GPX extensions nodes

Fixes #1791.
Add tests for GPX extensions
Update to use the correct default style function namespace
Test to make sure that feature styles take prececence
Move defaults style into `style.js`
Merge pull request #2394 from tonio/style_order

Give precedence to feature styles
Write version in builds
Merge pull request #2442 from tsauerwein/build-version

Write library version in build files
Merge pull request #2420 from gingerik/gpx-extensions

PR for GPX: read extensions tags
Unconditionally add version info to the build header

This reworks the changes in #2442 so we always include the version info, regardless of whether the module is run as main or not.  This also addresses a few lint related issues.
Merge pull request #2446 from tschaub/version

Unconditionally add version info to the build header.
Improve wording of ol.Map description
Merge pull request #2449 from probins/patch-1

Improve wording of ol.Map description