Avoid copying and removing uploaded files.
Configurable upload cache directory.
Increased upload file size limit.
Will try to add support for .ps generation.
Removes garbage cache files left by carrierwave.

Apparently, if the validation fails, carrierwave does not remove the
uploaded file from the upload cache dir.
Added support for PostScript generation.

Also, a new couple of options were added to application.rb in order to
control the behavior when there's a processing error on a given
document.
Changed default value for option.