Add posibility for disabling copying files to tmp folder

[C-h-e-r-r-y]

Now every sql which is loaded by plugin is copied into tmp folder, but sometimes it is not neccessary. For example in case when mysql dump is executed. It can be a couple gigabytes long.

Could you please add property to disable sql files copying into tmp dir?

see also stackoverflow question - http://stackoverflow.com/questions/35498761/how-disable-sql-maven-plugin-file-copy-to-temp-folder