Update site/Docs/Contribute/Contributing-to-NuGet-Documentation.markdown

Attempting to clean up some of the formatting on "Sample Markdown" page.
Make prettyprint work
warning of doom and gloom

with a side of aww, shucks.
FAQUpdate

Added sections to FAQ and added some new FAQs.
Revert "FAQUpdate"

This reverts commit 027b3a778fae99439aec63465095fbc8f910283a.
Restructed FAQ and added new FAQs
Update NuGet-Config-File.markdown

added nuget extensibility point
Update Configuration-File-and-Source-Code-Transformations.markdown

Add XDT feature description
Update Configuration-File-and-Source-Code-Transformations.markdown

fix a typo
machine wide config
added the screenshot
machine wide config updated
Merge branch 'nuget-2.5-deepakv' of https://github.com/NuGet/NuGetDocs into nuget-2.5-deepakv
Merge branch 'master' into nuget-2.5-deepakv
removed c:\temp from the screenshot
NuGet Group Policy Spec
Update Group-Policy.markdown
Added a link to the codeplex discussion for group policy
Made the link a link
Update Group-Policy.markdown

Updated the doc to cover DefaultPushSource configuration