FinderQuery renamed to ArrayFinderQuery. Non-functional changes only.
Remove Model#method_missing. Confusing and questionable value-add.

#method_missing should in general always call super if it doesn't resolve to something. Assuming a method-not-found was an attempt to access an attribute is arguablly a big assumption.
relation_column? should be class method. Add .virtual_relation_column?
Copy Model code to ArrayModelAdapter, unchanged.

Code will be split between the two modules in later commit.
Separate Model and ArrayModelAdapter code. Specs passing.

Note: existing models must now include MotionModel::ArrayModelAdapter
Merge pull request #22 from aceofspades/array_adapter

Array adapter