Remove github.com references

* 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)

test/test_folder_size.py

@@ -49,8 +49,7 @@ def test_get_folder_size(args, tmpdir):
 
     # Check if the size is correct. Unfortunately, the `du` call
     # in pmb.helpers.other.folder_size is not very accurate, so we
-    # allow 10kb of tolerance (good enough for our use case):
-    # <https://github.com/postmarketOS/pmbootstrap/pull/760>
+    # allow 10kb of tolerance (good enough for our use case): #760
     tolerance = 10240
     size = 204800 * files
     result = pmb.helpers.other.folder_size(args, tmpdir)

test/testdata/init_questions_device/aports/device/device-lg-mako/APKBUILD

@@ -4,7 +4,7 @@ pkgname=device-lg-mako
 pkgver=2
 pkgrel=16
 pkgdesc="Google Nexus 4"
-url="https://github.com/postmarketOS"
+url="https://postmarketos.org"
 arch="noarch"
 license="MIT"
 depends="linux-lg-mako mkbootimg mesa-dri-swrast"

test/testdata/init_questions_device/aports/device/device-sony-amami/APKBUILD

@@ -2,7 +2,7 @@ pkgname=device-sony-amami
 pkgver=2
 pkgrel=0
 pkgdesc="Sony Xperia Z1 Compact"
-url="https://github.com/postmarketOS"
+url="https://postmarketos.org"
 arch="noarch"
 license="MIT"
 depends="postmarketos-base mkbootimg mdss-fb-init-hack mesa-dri-swrast"