add delivery receipts for private muc msgs & enable update last-seen for muc-msgs

# enable update last-seen for muc-msgs

Added multiple select to Choose Contact Activity (squashed)

When passing the Choose Contact Activity a boolean called "multiple"
set to true, it now allows the user to select multiple contacts. Long
pressing a contact enters multiple selection mode and the selection is
confirmed using a button in the CAB. The Activity returns whether or not
multiple contacts were selected using the same boolean. If multiple
contacts were selected, an array of JID strings called "contacts" is
returned. The Choose Contact Activity now also honors "filter_contacts",
an array of strings containing JIDs that should not be displayed in
the picker.

The invite to conference dialog now uses this feature to enable inviting
multiple contacts at once. Additionally, Invite Contact uses
"filter_contacts" to only display contacts that are not yet
participating in the conversation

Green led color is better with "full-green"

Set file size also for cached avatars

disable all really weak cipher suites

With #959 all ciphers of the platform were enabled, but this also
includes several suites that are considered as very weak, even down to
NULL- and anon-ciphers which disable completely disable encryption
and/or authentication. Especially the anon-ciphers could be easily used
for a mitm-attack.

To remove all weak ciphers a blacklist with patterns of cipher-names was
added to Config.java. The blacklist is based on the "mandatory discards"
that Mozilla suggests to not use for TLS-servers because they are weak
or known to be broken.
https://wiki.mozilla.org/Security/Server_Side_TLS#Mandatory_discards

display geo uris as location. show 'send loction' in share menu if request location intent can be resolved

Some changes to the LED color in notifications !

Revert led light color

- Update mBuilder in NotificationService.java to ensure that the led is displayed at the right color.
CF: http://stackoverflow.com/questions/14953793/android-notification-led-doesnt-use-my-color#comment20991762_14953793
- Changed led Color to green to remember the icon color and led times