Update errno in get/setpriority()
- Added definitions for process states - New PCB fields
Fixed some whitespace errors
Proc vm development
Merge branch 'master' of github.com:OlliV/zeke

Fixed conflicts and compilation errors due to merge.

Conflicts:
	src/proc.h
Various fixes

- Adds COW flag
- Fixes bug where cpu mode was not restored correctly after a syscall
- Fixes some compilation warnings on dynmem
VFS write functions

- Adds unistd write() and pwrite()
- Can now write messages to KERROR stream from kernel threads/processes
  even from usr mode by using write() and strerr.
- Declares some kernel process attributes to be used from kworkers or so
vm and sched changes

- Some changes related to copy-on-write vm things, should not break
  anything but it doesn't add any functionality yet
- No need for kmalloc in sched.c
Fixes pt attach bug on startup

Fixes bug where MMU code can't attach page tables properly because proc
has not initialized cur_proc variables.
Copy-On-Write virtual memory

MMU code now fully supports COW and proc can handle cow but proc can't
yet mark any regions as COW and we are also missing sufficient memory
allocating and mapping method for processes.