Update VLAN ID list for SIX
[DB] Schema update to VLANs table

Allows an admin to decide if a given VLAN should be included in the peering matrix or peering manager.

SQL update required:

```mysql
ALTER TABLE vlan ADD peering_matrix TINYINT(1) NOT NULL DEFAULT 0, ADD peering_manager TINYINT(1) NOT NULL DEFAULT 0;
```
[NF] Front end glue for new VLAN peering matrix / manager columns
[IM] Remove hardcoded INEX VLAN details - fixes #178
[IM] Remove hardcoded INEX VLAN details for peering matrices

Allows admins to set which VLANs should form part of the peering matrics.

Includes IPv6 selection bug fix.
Merge branch 'nf-vlan-pm-switches'
Version bump
Merge remote-tracking branch 'remotes/inex/master'

Conflicts:
	application/Repositories/Vlan.php
[BF] Auth issue for password resets
[IM] de-inexify peering manager - fixes #180

Documentation updated at:

https://github.com/inex/IXP-Manager/wiki/Peering-Manager
Version bump
Merge tag 'v3.7.1'