Merges branch 'release/0.1.1' into develop
Improves lazy evaluation in child containers.

Fixes #4.

Item lookups now pass around a reference to the container that contained
the original lookup. Injection is done using the originating container
when present. Thanks to @nicops for reporting this.
Bumps version to 0.1.2
Merges branch 'release/0.1.2'