* Travis and Coveralls badges
* aports: instead of <https://github.com/postmarketOS>, use
<https://postmarketos.org>
* References to full URLs to issues and pull requests replaced with
a hash and the number
* grsec check: simplify error message, remove link to github issue
(nobody is using that anymore anyway)
* Removed obsolete apkindex_files cache testcase (the corresponding
function has been removed in #345 already).
* Fix test_challenge_apk: It failed on Travis, because we're accessing
/etc/abuild.conf, which only exists after initializing the build environment.
It's a random dummy file anyway, so I've replaced it with another file.
* Fix test_folder_size: accept a tolerance in the result
* The system image size is now calculated as: root size - home size.
* New function in `pmb/helpers/other.py`: `folder_size()`, with a
testcase.
* Instead of copying everything to the system image folder, and
deleting the home folder afterwards, do not copy the home folder
in the first place.
* Added `pmbootstrap -s` to skip generating the initramfs for faster
debugging.
* Set the default value in the "are you sure, that your partition has
at least..." to "y", so we can run `yes '' | pmbootstrap install`
to make it run through the whole installation process.
* Increase full size to 120%, boot partition gets 15 MB free space now