Added an ignore pattern for VS project upgrade artefacts.
Removed un-used using statements.
Added support to display local images via a relative path based on Markdown file location. (E.g. ![Logo](Images/logo.png))
Added support for navigation to linked solution documents in the preview window.

Overwrites browser navigation behaviour if a link can be resolved to a document
within current solution. This allows linking to (opening) files in the current solution
when a link is clicked in the preview window. By linking to other Markdown files in
the solution a site (wiki) like experience is achieved.

E.g.
[Home](../Readme.md)
[More](Readme.more.md)
[Code](../MyProject.Web/Properties/AssemblyInfo.cs)
Resolve a merge regression.
Updated transform documentation.