Some tests did't delete temporary directories.

Processing of downloaded messages is now finished before the next
download is started.

This way it will end up in the tarball generated by MMS Logger app,
and it's generally useful for debugging.

It's not being used at the moment but we may need it soon.

We need to use org.nemomobile.ofono.ModemManager API to notify ofono
that we need to download MMS so that it enables mobile data for the
appropriate SIM. If it's different from the currently selected data SIM,
then connman will be prevented from using mobile data while MMS download
is taking place.

These are mostly for convenience, the actual OBS build is using makefiles.

This makes the log easier to read.

Allows to forward operator's errors messages to the user.

New method readReportSendStatus has been added to org.nemomobile.MmsHandler
D-Bus interface. It's called when mms-engine is done with sending the read
report, successfully or not. If read report sending fails, the handler has
a chance to retry.

1. Remove DOCTYPE declaration. Other vendors are not doing that. Also,
   W3C seems to have removed http://www.w3.org/TR/REC-smil/SMIL10.dtd
   from their Web site, making this external entity invalid.
2. Add width/height units. CSS2 spec says that units are mandatory
   unless the value is zero.
3. Don't define the region if there are no items in that region.
4. Make region layout non-overlapping

All that should make MMS service side software happier.

Use gssize instead of size_t

It disables timeout for debugging.

Additionally, move it from the directory with the fake id to the directory
associated with the message once we know which id commhistoryd has assigned
to this message.

These changes are only useful for debugging, if mms-engine is started
with -t option. They have no effect on the normal operation.

So that it's clear what is a test and what isn't