MDL-43839 core: changed the default theme from standard to clean
MDL-43839 theme: add a file of css tweaks just for the installer
Merge branch 'MDL-43839_clean_default2' of git://github.com/andyjdavis/moodle
MDL-43837 behat: Adding reduced timeouts

There are steps where we want to check that
"something" does not appear in the page
or does not exist. We still have to spin
but we don't need to spin for 6 seconds.
MDL-43839 behat: Log out compatible with clean

.navbar needs to be clicked before following
log in or log out links.
MDL-37658 core_admin: Added behat step to navigate from navigation/Admin block

This step will help navigate to different parts of moodle
using navigation or adminstration block.
MDL-43839 behat: Other behat fixes (TO SQUASH)