Touch exclusion area added

[Haidery]

• Basically we gave user ability to exclude area from the color plate. This is useful to exclude any dark colors in centre or if you want your color plate to host a control inside it.

[RSully]

I tried to test this but can't get it to work. Could you explain usage or update the sample app with an obvious example?

Also you made some changes like setting the default color to blue and making the selection view size smaller. Unless these are necessary for this patch they should be reverted.

Last, it looks like you just updated one of the unit tests. If this truly is changing the functionality then I would suggest creating tests for this feature separately.