created resource to return all inventory

Added inventory and util packages. Added Class ToJSON with method
returnAllPcParts. Will be improving on methods in next commit.
changed returnAllPcParts method to return a Response

improved method, return an HTTP Responce, not a string variable, which
is just attached behind the sceens by Jetty to the HTTP responce,
without us having any way to control it.
added encoding for our html output

Add ESAPI library file to our project and implemented varchar encoding.