Add tests

[Permafacture]

Use some testing framework to make sure that the Allocator and any other core functionality is working correctly. create a few arbitrary components, and add values. make sure the values are what you put in. delete a few entities (from the top, from the bottom, from the middle, contiguous ones,not contiguous ones, etc.) and see if everything is still as expected. add some more entites. Complex data types, ints and floats. what happens if numpy wants to upgrade the type (int to float, float32 to float64?). I don't think multi-dimensional components work right now, but write tests for them anyways while your at it. Write tests for things that don't work yet so we can make those tests pass later.