Updated OpenMRS version reference to 1.9.4.
Implemented a double-entry stock operation system that replaces the previous transaction stock system.
	Updated table creation scripts and hibernate mappings.
	Created core Stock Operation services and models.
	Created unit tests for stock operations and implemented them.
	Updated application context to remove old services and add new ones
	(^inv-17, ^inv-21, ^inv-26, ^inv-30) Completed