serializer attempts to deserialize mutipart form data on post

[emil-perhinschi]

If a serializer is set (JSON or Mutable) and a "multipart/form-data" request is sent the deserialization of the whole 'multipart' section of the request is attempted starting with and including the boundary.

A very basic Dancer2 app is included in the tar.gz archive, run the second test.

test_uploads.tar.gz

A quick solution in this pull request https://github.com/PerlDancer/Dancer2/pull/1678

[cromedome]

Thanks for the bug report! Please see my comments on #1678.

[emil-perhinschi]

"undefined" warnings solved