Runtime vars are now grouped into cache lines.

Signed-off-by: Michael Lippautz <michael.lippautz@gmail.com>
Lot's of renaming:

* global sbrk allocator -> arena
* LargeObjectAllocator: LargeAllocator
* src/arena -> scalloc_arenas.h: now contains all arenas used in scalloc
* PageHeap -> SpanPool
* DqSqAllocator -> BlockPool

and others.

Signed-off-by: Michael Lippautz <michael.lippautz@gmail.com>
New getter for span header.

Signed-off-by: Michael Lippautz <michael.lippautz@gmail.com>
Fixed tests.

Signed-off-by: Michael Lippautz <michael.lippautz@gmail.com>
Default settings are more usable now :)

Signed-off-by: Michael Lippautz <michael.lippautz@gmail.com>