Fix #3790:

- Do not let 2 interfaces to setup the same track6 prefix id
- Show correct prefix id range for each interface
Fix #4099:

- When interface is 'lo0', strpos returns 0, that is erroneously
considered false (boolean) on the test. Be more strict on strpos return
to avoid skiping lo0 ip aliases during sync.
Fix indent and spaces
Split ICMP and ICMPv6 types on Firewall Rules

- Remove redundant declaration of $icmptypes and move it to a common
place (filter.inc)
- Add missing ICMP types for v4
- Add ICMPv6 types
- Adjust javascripts to show correct options depending of IP Protocol
- Hide ICMP type selection when protocol is IPv4+v6

It fixes #3389
Base URL must be specified when alturlenable on

I had a 2.1.5 system that I was wondering why the dashboard always said it could not check for updates. I discovered it had "Use an unofficial server for firmware upgrades" checked, but the "Base URL" field was empty.
That can easily be checked with input validation - might as well catch dumb things like that.
I thought about making it parse the string to see if it seemed like a "valid" URL. But so many strings seem like valid URLs:
var_dump(parse_url("abc"));
array(1) {
  ["path"]=>
  string(3) "abc"
}

It seemed a bit pointless to bother - if the user puts something in then hope that it might point to something some day.
Merge pull request #1381 from phil-davis/patch-8
Fix password confirmation name to make style working as expected. Fixes #3992
Regenerate pfSense.pot
Update Turkish translation file from last version available on old translation server
Update po from last pot
Regenerate Turkish mo
Merge remote-tracking branch 'upstream/master'