[semi-passive plugin] Modification of most of the semi-passive plugins.
[semi-passive plugin] Update Session management schema plugin.
[net/active plugin] Update older plugins.
[net/bruteforce plugin] Update older plugins.
Merge branch 'classful_plugin' of https://github.com/depierre/owtf into classful_plugin

Conflicts:
	plugins/net/active/smtp@PTES-002.py
	plugins/net/active/snmp@PTES-010.py
	plugins/web/semi_passive/Search_engine_discovery_reconnaissance@OWTF-IG-002.py
[plugins] Fix typos
[web/active] Update Nikto plugin.
[plugin] Implement get_filename_and_extension.