#392 CopyrightHref with "mailto:" or relativ path

[andor]

An exception will be thrown if you set
the "CopyrightHref" to an "mailto:xyz@abc.us" or a
relativ path like ".\foo\bar.blah". But this should be a
valid href or url.

The following Exception-Stack was created:
An error occured while trying to build the documentation.

Exception: NDoc.Core.DocumenterException
Illegales Zeichen in dem Pfad.

Exception: System.ArgumentException
Illegales Zeichen in dem Pfad.

Exception: NDoc.Core.DocumenterException
at NDoc.Documenter.Msdn2.Msdn2Documenter.Build
(Project project)

at NDoc.Gui.BuildWorker.ThreadProc()

Exception: System.ArgumentException
at
System.Security.Permissions.FileIOPermission.HasIllegalCh
aracters(String[] str)

at
System.Security.Permissions.FileIOPermission.AddPathList
(FileIOPermissionAccess access, String[] pathListOrig,
Boolean checkForDuplicates, Boolean needFullPath,
Boolean copyPathList)

at System.Security.Permissions.FileIOPermission..ctor
(FileIOPermissionAccess access, String[] pathList,
Boolean checkForDuplicates, Boolean needFullPath)

at System.IO.File.InternalCopy(String sourceFileName,
String destFileName, Boolean overwrite)

at NDoc.Documenter.Msdn2.Msdn2Documenter.Build
(Project project)