Introduce -d, -v options to list command

-d, --dir, show directories
-v, --variants, show variants
Fix error output redirection

This fixes issue #303
Checking in changes prior to tagging of version 1.14.1.
add badges
update readme
Fix badge
Merge branch 'master' into develop
avoid warnings when https://downloads.php.net/<release-manager> link is down
assume +default variant when no build config is given, closes #313
remove code duplication on bin/phpbrew