Toolchain fixes

This is the MR for the similarly-named milestone, estimated time of 1 week.

.gitlab-ci.yml

@@ -63,12 +63,6 @@ stages:
     key: "macosx-cache"
 
 
-build_linux_27:
-  <<: *linux_build_job
-  variables:
-    PYTHON_VERSION: "2.7"
-
-
 build_linux_36:
   <<: *linux_build_job
   variables:
@@ -131,7 +125,6 @@ browser_linux_36:
   script:
     - ./_ci/deploy.sh
   dependencies:
-    - build_linux_27
     - build_linux_36
     - build_macosx_36
   tags: