Added tag <epayload> to the payloads.xml's <test> tag to define which payload to use when exploiting the test type.

Removed some useless tests.
Moved <error> from queries.xml to payloads.xml as it makes more sense.
Beeps at sql inj found only if --beep is provided.
Minor fix in order to be able to pickle advancedDict() objects.
Minor code refactoring.
Removed useless folders.