Wrap all ViewEngines in a profiler

Wrap all ViewEngines in a custom profiler view engine, using the
ProfilerResolver to track performance
Make sure the profilingengine doesn't wrap itself
Merge pull request #146 from mortenbock/6.2.0

Custom ProfilingViewEngine
Finally got around to changing all calls to umbraco.IO to Umbraco.Core.IO - that'll clear up several hundreds of warnings :)
Merge branch '6.2.0' of https://github.com/umbraco/Umbraco-CMS into 6.2.0
Core.EnumerableExtensions - bugfix f9663a9
Core.StringExtensions - fix methods that should be extension methods
Core.StringExtensions - adjust to new default IShortStringHelper (see f64b8d6)
Merge remote-tracking branch 'origin/6.2.0' into 6.2.0-pubcontent

Conflicts:
	src/Umbraco.Tests/CodeFirst/ContentTypeMapper.cs
	src/Umbraco.Web/Models/DynamicPublishedContent.cs