Support for `"display=none"` #66
Update SVG Viewer Test Project

Updated to .Net Framework 4, added some code to finish test, & removed
extraneous files. I updated this project so I could test the changes for
#66
Requested Changes from PR #67 Review

Moved Display="none" hack & Added .Render check for : if (!Visible ||
!Displayable)

Also, minor change to logic of SvgBoolConverter so bad visibility values
(other than "hidden" or "collapse") wouldn't accidentally hide element
Merge pull request #67 from csmoore/master

Support for `"display=none"` #66