Fixes: U4-2006 Domain.GetDomain(string DomainName) is case-sensitive
Replaced HttpContext.Current.Cache with HttpRuntime.Cache
Add validation for regular expression property
Add UI validation for regular expression property
Merge pull request #230 from Yawka/U4-2772

U4 2772
Merge pull request #221 from AnthonyCogworks/U4-2272

Replaced HttpContext.Current.Cache with HttpRuntime.Cache
Merge pull request #220 from leekelleher/U4-2006

Fixes: U4-2006 Domain.GetDomain(string DomainName) is case-sensitive
Merge remote-tracking branch 'origin/6.2.0' into 7.0.2

Conflicts:
	src/Umbraco.Web.UI/umbraco/controls/GenericProperties/GenericProperty.ascx
Fixes some merge issues