mailchimp 3.2.0-rc2

This release moves two long-standing submodules into their own separate projects: Events and Campaign. The `3.2.x` branch requires that these modules still be present on your site, so as to avoid any upgrade surprises for users who utilize those modules. You will see that the new, independent versions of these modules are required in composer.json. Upgrading from the 3.1 branch should be simple: a cache clear is the only installation step after letting Composer handle the module updates.

The next major release (4.x) will remove this dependency from composer to allow sites that do not utilize the specific functionality in these submodules to exclude them from their codebases. This is because it is understood that these submodules or not commonly used.