Merge pull request #902 from emanuele45/contact_me

Change the "receive PM from" to "members allowed to contact me"
First version of a notification system, kept quite generic, it can accomdate almost anothing post-based

Signed-off-by: emanuele <emanuele45@gmail.com>
Mark notifications as read + some buttons + link tree + etc.
adding atwho

Signed-off-by: emanuele <emanuele45@gmail.com>
Fixed default sorting (not really sure it is correct though)

Signed-off-by: emanuele <emanuele45@gmail.com>
Couple of tweaks

Signed-off-by: emanuele <emanuele45@gmail.com>
Added db schema and changed column name from type to notif_type

Signed-off-by: emanuele <emanuele45@gmail.com>
Missing field in install, fixed prefix (Thanks TE), added upgrade

Signed-off-by: emanuele <emanuele45@gmail.com>