increase wordwrap width to 90

fixes display of long 'wp core config' example
Turn `validate_role()` into a more helpful method and apply it in more places
Also validate `wp user remove-role`
`$role` can be empty for `wp user generate`
Add some tests for error conditions with roles
Changed dump into export.
Merge pull request #1056 from clemens-tolboom/feature/dump-should-be-export

Changed dump into export.
show error when invalid format is passed
move --format=ids handling to individual commands
Merge pull request #1058 from wp-cli/format-ids

move --format=ids handling to individual commands
test that failure is due to expected error
Merge pull request #1053 from wp-cli/valid-role

Turn `validate_role()` into a more helpful method and apply it in more places
throw error when wp-config.php looks invalid
Merge pull request #1059 from wp-cli/fix-992

throw error when wp-config.php looks invalid
show full command name in usage output; fixes #1016
Support for network-activating a plugin upon install

Usage `wp plugin install user-switching --network`
Use the `$current_site` global instead of `wpmu_current_site()`, which is being removed in trunk

See http://irclogs.wordpress.org/chanlog.php?channel=wordpress-dev&day=2014-03-04&sort=asc#m803847
run functional tests against WP 3.9-beta1
Merge pull request #1052 from wp-cli/fix-1052

New site creation broken against trunk
Change syntax from `--network` to `--activate-network` for clarity