change data directly in mysql for some tables

search-replace on tables that don’t contain serialised data can be
changed directly in mysql
If the plugins directory doesn't exist, create it before installing
Fix copy pasta
Support for automagically creating the theme directory too
Allow updating core directly from a ZIP file

Previously, updating core from a ZIP file also required passing `--version`
Test coverage for permitting updates from file without specifying version
Merge pull request #1242 from wp-cli/update-from-zip

Allow updating core directly from a ZIP file
Fix silly copy and paste error again. `hello` exists in WP.org as `hello-dolly`
Need to register the theme directory after it's been created
Merge pull request #1238 from wp-cli/create-directory

Create plugins / themes directory if it doesn't exist
List meta for an object, demo commit
Special treatment for JSON, and tests that fail because meta_value isn't unserialized
Throw warnings if the plugin is already active
When a given theme is already active, provide a contextually appropriate message

Also prevents triggering of `switch_theme()` if the theme is already activated.
Messaging more consistent with the rest of `wp plugin`
Test cases for these warning messages
Merge pull request #1248 from wp-cli/already-active

Throw warnings if a plugin is already active
Network-only plugin check should only happen on multisite
Merge pull request #1250 from wp-cli/network-only

Network-only plugin check should only happen on multisite
Move this to its appropriate place