HSEARCH-1273 Adding tip about default spatial field name org.hibernate.s...

...earch.annotations.Spatial.COORDINATES_DEFAULT_FIELD.

Also reviewing and fine tuning rest of spatial chapter.
I am aligning w/ the rest of the code examples and our source code. I also prefer the order we choose in out tests. if you where to write production code which order would you take? Primarily we are dealing with an ORM entity, then it is indexed as well and by the way it is using spatial. For me there is a logical order implied.