Add Highlight Text Fragments button to ribbon
Add Ribbon codebehind for HighlightTextFragmentsButton
Add Highlight Text Fragments Class (with dummy method) and wired up to project.
Add dummy code for highlight. Need to implement.
Add basic implementation. Need to fix one fragment case, resolve multi line split and refactor.
Add support for animation for grouping multi-line selections
Remove support for multi-line grouping highlight support due to possibly ugly transition animation. Instead, split multi-line highlighting into multiple consecutive highlights
Add custom color support
Re-added shape grouping
Fixes #423
Added appear animation
Add test file for text fragments
Add Icon for ribbon
Add icon and fix context menu absence for tetradic 4
Merge branch 'Feature-ColorPicker' into dev-1.8
Merge branch 'Issue_288' into dev-1.8

Conflicts:
	PowerPointLabs/PowerPointLabs/Models/PowerPointSlide.cs
	PowerPointLabs/PowerPointLabs/PowerPointLabs.csproj
	PowerPointLabs/PowerPointLabs/Ribbon1.cs
update version info dev 1.8.4