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
Add better docs around authors mapping CSV.
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`
introduce is_windows() helper
Fix wp plugin delete on Windows
Merge pull request #935 from eliorivero/master

Fix wp plugin delete on Windows fixes #934
Perform `is_numeric()` checks before `is_email()`, as the former will be faster.
Support for using a user's email address in the `--user` flag.
Apparently this helper function exists