When setting cell value to RichText, don't use SetEnumerable.

Update version to 0.80

Clean up project files (#26) ...

* Remove SCC tags in projects.

* Correctly reference NuGet dependency.

* Remove dependency on System.Windows.Forms

* Remove all platforms except AnyCPU

* Remove reference to System.Windows.Forms in Tests project

* Remove old-style NuGet references

* Remove DocumentFormat.OpenXml.dll from Solutions. We reference it through NuGet.

* Remove OnBuildSuccess

Fix XLColor equals method (#25) ...

* Use ToArgb() to compare equality of colors, in order to return TRUE when comparing RGB(FF,FF,FF) to White.
http://stackoverflow.com/questions/8146453/system-drawing-color-equality-operator-doesnt-treat-0xffffffff-as-color-white

* Add test for named color vs RGB

* Update bespoke unit tests files to remove duplicate font styles.

* Set substringo of rich text to Garamond font, instead of Broadway. Broadway probably isn't installed on the AppVeyor server. Garamond is a much more common pre-installed font.

* Disable different font to see if it affects the AppVeyor build.

* Use Courier font for rich text. Hopefully this one is installed on AppVeyor.

Remove Code Analysis configurations, which are disabled anyway.

Project hierarchy cleanup