Initial commit for tooltip

Tooltip was made as it assumed to be. As it was expected, tooltip covers Scrollbar and user can not use the scroll with mouse until tooltip is opened. Please review code and close that pull request  https://github.com/DynamoDS/Dynamo/pull/2026 because it was made in the wrong brach. I apologize about that wrong pull request, that will not happen again.
Hi, Ben.
You mean that I should store images not in library in wich classes(e.g. 
Color, Arc etc.) was written?
Yors, Anna.
On 7/29/2014 10:15 AM, Ben Goh wrote:
>
> In src/Engine/ProtoAssociative/ProtoAssociative.csproj:
>
> > @@ -84,7 +84,10 @@
> >      <Compile Include="Properties\AssemblyInfo.cs" />
> >    </ItemGroup>
> >    <ItemGroup>
>
> I don't think we want |Engine| to be dependent on |PresentationCore|. 
> The idea is that |Engine| is a language runtime and it does not 
> understand anything about visuals. Please remove all these new 
> references that you have added. The annotation (e.g. tool-tip 
> description or icon image) of a library item should be a |UI-only| 
> thing, that is done outside of |Engine|. Typically how this happens is 
> having either an external XML file that describe how each class/method 
> is associated with the icon, and tool-tip description text; or we can 
> have another assembly alongside the original assembly that supplies 
> the annotation information.
>
> —
> Reply to this email directly or view it on GitHub 
> <https://github.com/DynamoDS/Dynamo/pull/2032/files#r15508870>.
>