Assignment 3 - Scheduler and memory drivers fixes

* Fixed Even scheduler strategy
* os_kill finished
* Fixes in os_memory.c
+ getter/setter for heap map entries
+ os_malloc
+ os_getChunkSize
* Adjusted heap member names in os_memheap_drivers
* Global var offset and use/map size calulations fixed
* Check for heap offset in os_core.c fixed

All provided test progs passed :)