Big merge checklist

If you are going to merge something big, and especially if this something big needs a new/updated dependencies, like Vc, libgsl or anything else, please follow this checklist to make sure your change doesn't introduce any unexpected problems the next day it gets merged :)

Create your own branch yourname-feature[-phabricator_id_if_present]
[OPTIONAL] Add a patch review to the Differential review board
If you your branch introduces/changes Krita dependency:
- send a mail to the mailing list asking people to build this dependency and test your branch
- ask sysadmins to update this dep on KDE CI system
Make sure you branch compiles on:
- Windows
- Linux
- OSX
- if the dep is optional, check if it compiles with the dep switched off
Ask Dmitry to check/update dependencies on Krita Lime
Now you are ready to merge!