Fix(annotation): annotationEdit initialise to the last color, drawType & force hex color comparaison to upper case

[panaC]

Fixes #2548

[danielweck]

Just in case Thorium receives a colour code from an external source, note that the RGB HEX syntax isn't necessarily #RRGGBB, see:

https://developer.mozilla.org/en-US/docs/Web/CSS/hex-color

In other words, the hexToRgb() regular expression will break with all other RGB HEX syntaxes. This might not be a problem right now if the function only consumes strings from Thorium itself, where the RGB HEX syntax is only #RRGGBB :)

[danielweck]

PS: in the highlights engine I just use rgb(rrr, ggg, bbb) instead of #RRGGBB as this doesn't need any format conversion, I can just pass the raw numbers from the IColor struct.
That being said, the RGB HEX syntax is of course easier to store in persistent state of during import/export stages, which I guess is why the conversion takes place?

[panaC]

Indeed ! Thanks you for your precision.