Improve squid group membership helper script

(cherry picked from commit 3314990c548d819e9232d46fed80b87b5980dd71)

Conflicts:
	main/squid/ChangeLog
	main/squid/debian/precise/control
Indentation fixes

(cherry picked from commit 6927f764026d52173f4c8fea72a957b2a40dda5c)
Retrieve nested group members for filter profiles in external AD mode

(cherry picked from commit afde75189d70b66192e8708070ba8c02ac3cba75)

Conflicts:
	main/squid/ChangeLog
Correctly escape DNs and search filters or external ACL helper script

(cherry picked from commit 841b15c5397fae42a1e3545417fbcbb27df9bb2d)

Conflicts:
	main/squid/ChangeLog
Fix warnings using numeric equal with strings

(cherry picked from commit 00e2094c0563104ecbca247394a2db98078c3dac)
Explicitly specify to listen on all IPv4 interfaces

(cherry picked from commit ffc6cd68caae288ee7bb9f351fd4d9ef935e50cb)

Conflicts:
	main/squid/ChangeLog
Add new config key auth_ad_negative_acl_ttl

(cherry picked from commit 35c4467cafede8ef016bccf49bae3d7724d73c7c)

Conflicts:
	main/squid/ChangeLog
	main/squid/conf/squid.conf
	main/squid/src/EBox/Squid.pm
Merge pull request #776 from Zentyal/scabrero/squid-backport-external-ad

Scabrero/squid backport external ad