Merge pull request #25 from griera/master

Implements sys_read system call and device-dependent routine sys_read>_k...
Merge pull request #26 from griera/master

All tests suite regarding to sys_read syscall are performed successfully
Merge pull request #27 from griera/master

First implementation of dynamic memory (sbrk syscall). From tests suite,...
Merge pull request #28 from griera/master

First final release of ZeOS
Clean TODOS and things