The 'sysctl' syscall has been strongly deprecated on Linux for ages.
Currently, on old architectures it will spam syslog whenever used, and on
newer ones it's missing from the headers altogether.  Opencv has migrated
away on Linux already, but #includes were left lingering.  This commit
removes them on non-__APPLE__, unbreaking x32 (and probably others).

Deleted multiplications by zero and consequent additions of zero terms.

LevMarq now doesn't outright fail, but doesn't seem to improve things
much if at all.

Refactoring of Cholesky decomposition.
Fix for memory corruption bug.
LevMarq as a whole still non-functional.

it is marked as obsolete

Signed-off-by: Yan Wang <yan.wang@linux.intel.com>

- added test for loading legacy files
- added version to new written models
- fixed loading of several fields in some models
- added generation of new fields from old data

used BufferPool mechanism instead