#1172 [SciTE] Customizable colors for folds

[desto]

I have added settings for .properties files to change the color of the fold points. (see screenshots)

fold.fore=#xxxxxx
fold.back=#xxxxxx

White boxes just don't look great when using a dark theme.

[Neil Hodgson]

Control over the fill colour would help those with dark colour schemes.
The patch makes all of the symbol choices #808080/#FFFFFF which is different and looks worse than the current default for 0 and 1 (#000000) and 2 (#404040/#FFFFFF. In general, new options should not change current default behaviour. New settings should also be documented in SciTEDoc.html.

[desto]

You're right, I'm sorry about that!
Here's the updated version including the doc.

[desto]

I guess I should also add these settings as comments to SciTEGlobal.properties.

[desto]

I just noticed that my settings didn't work with variables, so

my.color.fore=#558855
my.color.back=#112211
fold.fore=$(my.color.fore)
fold.back=$(my.color.back)

didn't yield the expected result. Well now it does, using props.GetExpandedString.
There are other properties acting the same way, so I updated them as well. These are affected:

caret.line.back
fold.highlight.colour
fold.margin.colour
fold.margin.highlight.colour
highlight.current.word.indicator
highlight.current.word.colour
selection.fore
selection.back
whitespace.fore
whitespace.back

Edit: The .zip contains all files I've changed so far.
- SciTEProps.cxx
- SciTEDoc.html
- SciTEGlobal.properties

[Neil Hodgson]

Committed changes to set fold colours as [65abd1], to allow variables in properties as [5b6119].