Theme revamp about quelea

[berry120]

As a further note - please don't open pull requests for this issue, we almost certainly won't accept them! It's something that needs to be very carefully considered, then implemented in a way that suits everyone as best we can. As such it's really only a task suited for the core dev team. Sorry about that.

[berry120]

Tentatively adding this to 2019.0. Don't hold us to this - it may slip. (This isn't something we want to release before it's ready.)

[berry120]

Scrollbar now added to the global themes panel at least.

[berry120]

All of the points we plan to cover in the theme revamp have now been addressed. This doesn't mean that we won't make further changes later of course, but it does mean the bulk of the big changes that have been planned for some time now should be complete and ready to go for 2019.0.

[DeeTigIT]

These are really major improvements on the Quelea software. My compliments! With all the pending contributions, improvements and fixes for the 2019.0 release, Quelea will make big step forward.

Here's a testcase on the default global song/bible themes.

Settings:

• Allow custom item themes to override global theme : OFF
• Global theme: default song theme : DEFAULT THEME, default bible theme: DEFAULT THEME

Schedule (1 song item has custom theme, 1 bible item with custom theme):

I changed the default song theme : BLUE IMAGE.
(I didn't make a change in the default bible theme)

After this change in the default song theme all schedule items, not only the song items but also the bible item, are projected with the new default song theme:

For the bible item I didn't expect that, as the default bible theme is still on: DEFAULT THEME
Is this intended behaviour?