FV::Lite : extract values retrieval logic

Since v4.05, CGI.pm get noisy when calling the param() method in list
context. For now isolate calling this method on its own, and locally
silence those warnings.
Block CGI.pm from 4.05 to 4.08

They are known to cause problems with multi upload files.
Merge pull request #13 from GeJ/PR_new_CGI

Fix recent CGI.pm changes