REF
clean up
refactor: get min of two iterators
ignore core dump files
add some scripts for running the tests/starting debugger
fix: avoid double free on pivot element
fix: do not decrement left if it is at position 0 already
fix: increment left only if not dead or taken
DOC
steal now copies pointers to all still active items from other place
add some TODOs; clean up TODOs for MemoryManager
TODO: check_correctness fails although the result seems to be correct
Fix: comapring blocks

Needs to be done via indeces and not pointers to blocks, since the latter might be changed by another thread
since we have one additional element in the VirtualArray, end now points to the last instead of last+1 item
TODO: using the iterators (instead of their indices) makes the assert fail sporadically
REF: simplify