Patch by Zarafa <http://www.zarafa.com/> - which allows non-RFC '7-bit' and '8-bit' encodings in the
Content-Transfer-Encoding headers. The second part causes a fallback on "default" value "7bit", when it
was invalid, making it the same case as when the header wasn't sent at all.

--- libvmime-0.7.1/src/encoderFactory.cpp				2010-10-31 19:57:12.533611083 +0100
+++ libvmime-0.7.1/src/encoderFactory.cpp.allow-alternate-encodings	2010-10-31 19:58:40.831276383 +0100
@@ -40,7 +40,9 @@
 	registerName <encoderQP>("bmoted-printable");
 	registerName <encoderUUE>("uuencode");
 	registerName <encoder7bit>("7bit");
+	registerName <encoder7bit>("7-bit");
 	registerName <encoder8bit>("8bit");
+	registerName <encoder8bit>("8-bit");
 	registerName <encoderBinary>("binary");
 }
 
@@ -79,7 +81,9 @@
 			return (*it);
 	}
 
-	throw exceptions::no_encoder_available();
+	// fallback on "default" value 7bit when it was invalid, making it
+	// the same case as when the header wasn't sent at all
+	return getEncoderByName("7bit");
 }