Fixes: #1181 - navbar link stays active when using changePage()

Clears the active button class on the pressed navbar button after a
pagechange.
Merge pull request #4579 from jasondscott/1181_ActiveNavBtn

Fixes: #1181 - navbar link stays active when using changePage()
Navbar: Added comment to code that has been added as workaround.
Docs: Changed all references from beta to 1.3.0-rc.1 to prep for release
bump the version to 1.3.0-rc.1
Docs: Fixed broekn CDN link to core 1.9.0
navigation method and event examples
move nav demo under widgets dir
correct relative paths
Popup: Factor our width constraint code for reuse.
Popup: Moving function fitSegmentInsideSegment into the popup prototype.