WiFi access points are hidden in some cases

If AccessPoint.compareTo() returns 0, the object are considered as
equal, and then one object instance is removed from the displayed
list. This is the case for AccessPoints wuth different security level
and different SSID case.

This is unfortunate since the user could by accident choose wrong
network if two networks exist for the same SSID but with different
case of security levels.

Added code for compareTo to also handle difference in Case and
different security levels.

Example of sorting after the change:
AP:         Security:
aa           WEP
Aa           None (previously hidden due to equalsIgnoreCase)
aa           None (previously hidden due to not checking security)
Bb           None

Change-Id: Ifa4a37a9b17159f00e3a900480ece4ff4f5bd89a