WIP: MemUtils/SoftBufferAllocMgr: Fix issues when allocating more HW buffers
This patch includes:
- Add MemBuffer::shallowCopy and use it in move constructor and assignment operator
- Keep track of requested buffer size in MemBuffer, needed on reallocation
- Initialise only new buffers in SoftBufferAllocMgr::allocBuffers
- Reduce to 32 KB the threshold for mmap allocation
Edited by Samuel Debionne