Proposal for issues #1937 #1938 and #1946 

#1937: split HttpPostRequestDecoder in 2 subclasses (Multipart and Standard) while still backward compatible by using HttpPostRequestDecoder as before
#1938: if Content-Type is not specified, reverting to standard application/octet-stream by default (Opera bug)
#1946: allow to set an upper limit on attribute size, for all type of attributes, including FileUpload

This is for Version 4.
(note old pull requests are dummies or closed)