sys_execv changes name of curthread to program path requested
Remove unnecessary as_create() in sys_fork()
Remove some comments from proc.h which are no longer relevant
Add tentative pagetable prototypes from pagetable API
Remove useless include from pagetable.h
Modify ram_getsize() to no longer zero out its markers to the first and last physical address. This change was done to support the pagetable_bootstrap. It needs to be able to look at how much ram is available before determining the size of the pagetable
Implement pagetable bootstrap
Modify PTE struct in the following ways:
	- 'cntrl' attribute renamed to 'control'
	- supervisor bit added to control
	- modify PTR_VALID macro to operate on a reference
	  rather than a pointer
Update pagetable return types and add pagetable global to mark initialization
Implement pagetable API functions
Complete implementation of pagetable API