Move chart edit tab to a composite widget, AgChartEdit
Code beautification
Merge branch 'master' into refine-ui
Fix typo in AG_CHART_EDIT conversion
Add AgHeaderBar class

It extends GtkHeaderBar, adding Astrognome specific buttons.
Make AgWindow use the new AgHeaderBar
Sanitize variable types

The many type casts were causing a real mess. The new approach seems
to have the same level of error proneness, while the compiler finally
reports warnings about wrong types.
Move the chart's web view to the UI definition

Fially! Thanks goes to tristan, KaL and ebassi on #gtk for the
guidance.
Move selection toolbar into tab_list

It is not used anywhere else, there is no need to include it in the main
wrapping grid.
Add chart loading progress bar
Update TODO file
Merge pull request #100 from gergelypolonkai/refine-ui

Refine UI a bit more