Fixed various documentation bugs.
First (very basic) API docs generated by ddox.
.gitignore update.
More nothrow and pure in componenttypeinfo.
Prototype merging is now nothrow.
PrototypeManager ctor is now nothrow.
Process registering is now nothrow.
Convenience alias for default entity manager.
nothrow: EntityManager ctor.
nothrow: addEntity()
More @safe pure nothrow in component type manager.
EntityRange.popFront() is now nothrow.
process()/preProcess()/postProcess() methods now must be nothrow.