Add NUnit.Runners package to the solution.

This is a solution-level package, not a project-level package. As such,
it adds itself to the .nuget folder and the solution file.
Add new environment script to set PATH, etc.

And call the script from the run-build script.
Fix #104: Add a Test task to the build script.

Execute the unit tests via nunit-console.
Add a bit of debugging info.

Log out the number of test assemblies found, and their paths.
Fix #123: Only need one @script tag in the Session/Index.cshtml
Make the voting button display to the right of the "action" buttons for your own sessions and it should align nicely for other sessions
Merge pull request #122 from adrianbanks/users-page

Add a users section to the admin area
Merge pull request #124 from ninjaferret/bug/session-list

Fix #123: Only need one @script tag in the Session/Index.cshtml

Merge issue: the index.cshtml ended up with two @script sections.
Merge pull request #125 from ninjaferret/feature/position-vote-button

The vote button should always be on the right, even if it is your own session.
Add a bit more debug output.

This isn't needed to resolve the problems, but it's useful in other
cases.
Re-target .NET 4.0 in the Tests project.

The build machine doesn't have .NET 4.5 installed (yet), and the Web
project is targetting .NET 4.0 anyway. This should resolve some warnings
in the build log, but I don't think it will resolve the build failure.
More debug output.

Dump the properties hashtable out to the console before each task runs.
Use -Include rather than -Filter.

This appears to be a difference between PowerShell versions: -Filter
works as intended in PowerShell 3 but behaves differently in PowerShell
2. Using -Include has the desired effect on both versions of PowerShell.
Merge pull request #111 from alastairs/build-run-tests

Fix #104: Make the build run the tests
Merge pull request #131 from adrianbanks/issues/128

Fix #128: Style the error page better and add a link to the GitHub issues
rename gravitar to gravatar
fix following a rebase onto staging