added ofParameter<ofColor>

[moebiussurfing]

added to addGroup too

[moebiussurfing]

sorry, my pr is kind of dirty
because it's including some garbage..
but also added multicontext to allow multiple instances without crash on exit.…
are you interested on this?

[prisonerjohn]

I thought you could just pass an ofColor already and it would automatically cast it to an ofFloatColor. Is that not working?

[moebiussurfing]

hey @prisonerjohn , here, with the main branch is not working like this:
ofParameter<ofColor> myOfColor{ "myOfColor", ofColor::orange };
ofxImGui::AddParameter(this->myOfColor);

Showing All Errors Only
/openFrameworks/addons/ofxImGui/src/ImHelpers.h:164:66: No viable conversion from 'ofColor_<unsigned char>' to 'int'

[moebiussurfing]

also, when adding a paramGroup with some ofColor params, they are not added neither:

                ofParameterGroup g{"group"};
                g.add(myOfColor);
                g.add(myOfFLoatColor);
                ofxImGui::Settings settings;
                ofxImGui::AddGroup(g, settings);

Also, we get this warning:
[warning] AddGroup: Could not create GUI element for parameter myOfColor

On my PR code I have implemented both cases: add ofParameter<ofColor> and addGroup.

This happens too with ofParameter<string> when bundled into a group. Should be nice to add strings too. (to show the text, or as input text maybe...)
ofParameter<void> is neither implemented.