Allow db export to accept all mysqldump args
Add assoc arg for arbitrary mysqldump args

Props @danielbachhuber
Implements wp term generate, Fixes #389.
Conflicts resolved.
Added Behat tests for term generate command
Merge remote-tracking branch 'upstream/master'
Taxonomy no longer has a default value for term generate
Term generate no longer makes redundant DB query for existing terms
Updated term generate test with new required parameter
Support for `user_email` as a third type of argument that can be passed to `<user>`
Update functional test with email case
Fix bug in wp site url
exit with an error when 'wp site url' is called on a non-multisite install
Add better docs around authors mapping CSV.
Merge pull request #923 from rodrigoprimo/fix-site-url

Fix bug in wp site url
let the user know that --user_login= doesn't work

see #926
media regenerate: add seq example
don't list all invalid attachment IDs

it gets too long when using `seq`
make 'No images found' message a warning
Merge pull request #932 from wp-cli/media-seq

Make `wp media regenerate` work better with `seq`