Userspace API includes.
Start of userspace API implementation.
Update test application to use userspace API.
Initialize first and second for default pair constructor.
Added pagetable destruction method.
Moved vmm_pagedir methods out of class definition.
Fixed bug in vmm_pagedir::destory.
Implemented locking and memory APIs. Added "zero" API for testing.
Locking and handles.
Changes to test program to use "zero" API.