Fix issue 334, supporting file operations in NUnitLite
Fixes #331
Add EmptyDirectoryConstraint to the NUnitLite builds (except Silverlight)
Enable parallel execution on NUnitLite under .NET desktop builds
Merge branch 'issue-334' into issue-333
Fix error under compact framework
Remove appveyor.yml change included in error
Remove appveyor.yml changes added in error
Remove unused line in appveyor.yml
Merge pull request #338 from nunit/issue-334

Issue 334 - adds file-related assertions and constraints to the NUnitLite builds that support it
Merge pull request #339 from nunit/issue-333

Issue 333, unties parallel execution from the NUNITLITE define, instead using a PARALLEL define and removes the distinction between the NUnitTestAssemblyRunner and NUnitLiteTestAssemblyRunner
Rebased the Portable branch on master and squashed commits.
Fixing the portable build after rebasing off master
Removed the Mixed Platforms platform that Visual Studio keeps re-adding
Use .NET Stopwatch under CF; fixes #328
Remove usage of obsolete defines
Merge pull request #342 from nunit/issue-328

Use .NET Stopwatch under CF; fixes #328
Merged in latest from master
Add Classic asserts to NUnitLite
Merge pull request #340 from nunit/issue-335

Add Classic asserts to NUnitLite