Start fix [ bug #1437 ] Securitu Issue

Some of them can be fix, because GETPOST even with 'alpha' test do not
warn if input is
"2%2F0%2F1234%3cscript%3ealert%2893275%29%3c%2fscript%3e"
for exemple

I don't have magical solution for this kind of security issue
Merge pull request #1645 from FHenry/3.5

Start fix [ bug #1437 ] Securitu Issue