Create new Common directory for shared code; put XmlHelper in it.
Move TestNameParser to Common folder
Move OutputSpecification.cs to Common folder
Use different namespace depending on where common files are included to avoid clashes
Add missing defines for release build
Add Internal trace logging to common code, shared by engine, framework and nunitlite
Add AssemblyHelper to common code; remove unused AssemblyReader from framework
Move tests of common code to common as well
Override TextWriter.Dispose(bool)
Merge pull request #258 from nunit/issue-223

Issue 223 - Common Code
Merge branch 'master' of https://github.com/nunit/nunit into feature-ignore-nunit2