Upgrading version to 3.5.2-dev
Destroy should remove "dropzone" prop from element

If there's need to destroy dropzone instance, and create it later, the
exception happens. Here are the tests & fix for that case.
Merge pull request #183 from soneta/develop

Destroy should remove "dropzone" property from element
Moved .withCredentials after .open to prevent IE10 InvalidStateError bug.

Fixes #179
Added download files.
Upgrading version to 3.5.2 (Fixed IE10s InvalidStateError bug.)
Merge tag 'v3.5.2'

Fixed IE10s InvalidStateError bug.