Ensure before / after events are executed independently

[adrians5j]

These events must be executed outside save process.

This means that once the save starts, immediately execute beforeSave, beforeUpdate, beforeCreate events, and only then start the actual processing of entity. The same goes for "after" events, execute them once processing has been completely done.

This was done simply by renaming current before and after events to __before and __after, making them internal events, and inserting new ones that follow the explained behavior.

Motivation:
Eg. onAfterCreate developer again calls this.save(), this save call would not work. Entity was still in "processing" state, and method would immediately return.

[coveralls]

Coverage increased (+0.03%) to 94.983% when pulling 53d8a7e on entity/afterSave into cbb94b0 on development.