mms: fix NPE in compose message activity onStart when in multi select mode

Change-Id: Icc522abbba6f7abf5e80f294ef18466de3345836
Mms: Add to no subject filter for mms messages

* Some carriers add a default subject if one is not provided.
* T-Mobile US adds NoSubject if no subject is added.

Change-Id: Ibed4383d33c24922bcf758862f5e0a9f0e3ed97c
Mms: Match count per thread to message per thread

The default SMS messages per thread is 10000, but the max
message counter is set to 5000. This causes the wrong input
number to be shown in the selection dialog, as it's not possible
to go above 5000 and reach the default which is 10000.

Change-Id: I8af30677db2c5c32030ead99f3aa41c5b5469336