Use option paramName if it is a string. No longer assume it is an array.
Apply option limitMultiFileUploads even when limitMultiFileUploadSize is defined.

Ensure neither limit is exceeded when uploading.
Merge pull request #2787 from dougdomeny/master

Apply options limitMultiFileUploads AND limitMultiFileUploadSize, check for options.paramName
Merge branch 'master' of https://github.com/blueimp/jQuery-File-Upload