Fix and update javadocs in KieBase

Fixed copy & paste errors in javadocs.
Minor updates to the javadocs:
 - using @link when appropriate
 - multiple small updates/enhancements
Merge pull request #32 from psiroky/patch-1

Fix and update javadocs in KieBase
JBPM-3832 - Provide API method to delete session from db
added note about name and location change of destroy method before final