Update addrspace API and implement vm_fault handler compatible with inverted pagetable
Write new prototypes for hash and as_copy
Implement new versions of addpage and hash to accept the process ID as an argument
Include locks around critical pagetable functions
Update addpage to return the pagetable index of the newly added page
Debug addpage, was once setting the incorrect process ID
Implement as_copy
Update sys_fork() to copy address space once the child process ID is known
Update kill curthread in trap.c to call sys__exit
Add kernel shell command to dump pagetable
New macro in pagetable header file for perfrom frame-to-index reverse lookup. getindex() now correctly finding pages