Adds Xamarin.Forms project for multi-platform test runner and enhanced the view model.
Adds a test filter box.
Filtering tests now updates the test counts.
Removes unused SkipCount property.
Adds test result filtering.
Tests no longer revert to "not run" status when being re-run.
Adds a 'figity' test sample.
Renames sample test runner.
Adds sample Android test runner.
Adds iOS sample test runner, although it doesn't work because of a Xamarin bug.
Updates NuGet package dependencies.
Updates .nuspec file.
Add missing reference for Android targets.
Updates Xamarin.Forms version.
Make TestResultPage internal.
Consolidate namespace and add README

The README is now displayed automatically when the package is installed.
The README has code snippets that can be copied directly into each device project.
The solution now builds the right projects on all platforms.
NuGet package builds with prerelease suffix now.
Adds release notes to .nuspec file.
Move test runs to background thread by default.

Responsiveness of the UI during a test run on iOS devices is particularly bad. So by moving them to a background thread by default we provide much better responsiveness, allowing the user to look at test failures, cancel the test run, etc.

Tests that require the UI thread can change the default.
Increments NuGet package version to beta2.
Add PCLTesting.Portable.dll to SL5 platform.
Increment NuGet package version to Beta3.