Don't save alpha channel in screenshots (fixes #1451)
Change screenshot colorformat properly
Fix access to invalid data on reception of packet with size 0
Log unhandled exceptions in connectionthreads to errorstream
Fix typo in default configuration file
Fix another typo in example configuration
Simplify and optimize schematic replacements
Fix typo in comment in chat.cpp
Node highlighting.
Bugfix: don't highlight air nodes.
Added configurable selectionbox width. Min width = 1, Max = 5
Reduce indentation of HTTPFetchOngoing

Also clean up some related things.
Use configured bind_address for HTTPFetch
Change default halo.png for better visibility.
Make config compatible with C++11
Add a .mailmap file

So I was checking out minetest and wondered how many developers there are
and how they development community is setup and such, so I decided to have
a look at the git shortlog. There were lot of double entries for some
persons, so it was harder to estimate the number of people involved.

By adding a .mailmap file, the overview of the authors is much improved
For details on the .mailmap file, see
https://www.kernel.org/pub/software/scm/git/docs/git-shortlog.html

Signed-off-by: Stefan Beller <stefanbeller@gmail.com>
Small changes to French translation (Petites modifications mineures)
Fixed french vocabulary/grammar errors

Notes (in french) :

72 msgstr "Ok" : OK est un acronyme, pas un nom, donc majuscules.
193 msgstr "Feuilles transparentes" : quel type de feuilles ? Trop vague.
213 msgstr "Filtrage anisotropique" : oxymore.
229 msgstr "Précharger les visuels d'objets" : doit être écourté (dépasse trop la bordure grisée)
Revert "Small changes to French translation (Petites modifications mineures)"

This reverts commit 4432e982616cd871cf1ae5c5706da09e98077433.

Exception: "Nom / Mot de Passe" --> "Nom / Mot de passe"
.travis.yml: fix possible issues

* use `pool.sks-keyservers.net` as keyserver as it's often more reliable
than `keyserver.ubuntu.com` as you can see with Google.
* put script to multiple lines
    * build out-of-source
    * use two CPUs
        * make seems to fail if $(nproc) is used unlike WeeChat. ZNC has
          same issue.
* mark build as failed if one job fails immediately without waiting for
all builds to finish.
    * this doesn't stop jobs that didn't finish before build was marked
    failed.