Maven and @Embedded annotation

Hi,

This pull-request introduces @Embedded annotation. Additionally, I migrated microorm to maven to make build and test process easier. (it's a little problematic to configure robolectric with all its dependencies properly without it).
Important note: my code uses getDeclaredFields() instead of getFields() when getting an array of class' Fields. This makes us able to access fields with private modifier, which is pretty useful. Anyway, it does not return fields from subclasses. Supporting subclasses fields is rather trivial to implement, but I have some doubts in supporting this behavior so I decided to leave it as it is.

An example of @Embedded use can be seen in EmbeddedTest. (but I guess we should add some sort of samples maven submodule for such things as well).