enhance preset notification on configChanged

[panaC]

Each new imported publication inherit from the default global readerConfig settings, (they're a kind of fork of the readerConfig). Each publication become independent, the user setting up the local readerConfig attached to the publication and can apply this readerConfig settings to a global registry called defaultReaderConfig. It's a global preset across the entire publication. When an user want to apply this global configuration to his current publication, he need to call back from the reader navigation preset menu. This is the new Thorium 3.1 behavior, there are an independent global readerConfig preset.

Now, I make the observation that the preset menu section is not very clear at all. It's difficult to call back and apply to the global readerConfig preset registry. We can't know when a divergence appears between the current local readerConfig publication and the global readerConfig preset. So that we propose Arthur and I is a discrete notification when there is a mismatch with the global readerConfig preset. We added a small bubble with fade-in, fade-out at the end of the "preset" trigger button in the readerMenu. When a mismatch occurs there is a lightly flashing round warning you, that you can save your local readerConfig settings to the global readerConfig registry, and then apply it to any other opened or not publication in Thorium.