Simplify CommandRunner constructor
Move system environment settings to setup()
Merge branch 'master' of https://github.com/bolt/bolt into hotfix/commandrunner-refactor

Conflicts:
	app/src/Bolt/Composer/CommandRunner.php
Missing $this->
Only setup Composer if we're in read/write mode
Merge pull request #1888 from GawainLynch/hotfix/commandrunner-refactor

CommandRunner refactor