Added ToolTipService.ToolTip which binds to same property as its Text field on pages with titles where TextTrimming is used (i.e MapPage, MainPage, PortalItemPage, etc.)
Added ToolTip on PortalCollectionGroup showing webmap thumbnails.
Merge remote-tracking branch 'origin/v.next' into jNery/issue28_ToolTipOnTrimmedTitles
Merge pull request #50 from Esri/jNery/issue28_ToolTipOnTrimmedTitles

J nery/issue28 tool tip on trimmed titles