Renamed GetAddresses to GetMailAddresses.
Made sure that GetMailAddresses finds correct addresses when the DisplayName part contains a comma.
Removed looking for semicolon as I cannot find this in the mail spec and don't have any example mail headers containing semicolons to separate mail addresses.
Merge branch 'master' of github.com:jvdvleuten/aenetmail

Conflicts:
	Tests/HeaderDictionary.cs