micronode_get_node_types caches result incorrectly

Problem/Motivation

First, thanks for the excellent module!

I'm reporting this bug, but it was actually discovered by my teammate @iarla, so hopefully we can give him credit when the time comes. :)

We're calling micronode_get_node_types() as part of some custom entity autocomplete functionality.micronode_get_node_types is getting called on the same request somewhere else with a different argument. That result is getting statically cached with drupal_static and being returned when we call micronode_get_node_types with a differnent argument. So we end up getting the opposite of what we want! Oh no!

Steps to reproduce

Call micronode_get_node_types with different arguments during the same request. See fail test.

Proposed resolution

Replace drupal_static with a cache service. drupal_static is kind of on the way out anyway.

Remaining tasks

Patches to follow.

User interface changes

None

API changes

Fix to caching bug in API

Data model changes

None