Ipyexperiments

- fix bug in ipython callback functions definition
- add cl_set_seed=SEED to automatically reset the seed to a fixed value in each cell

- workaround for unreliable peak thread (avoid negative numbers)
- add locking to avoid thread race-condition

- dynamically format column widths in reports
- add , in large numbers (1,000)

- Delta Peaked calculation fixed in case of consumed memory being negative (released)
- switch to pynvx's pynvml wrapper

- fix MANIFEST.in to include project sub-dirs

- use pynvx as pynvml replacement on mac OS (thanks phenomax)
- switched GPUMemory tuple order to be consistent with nvidia meminfo
- handle the situation where a mem peak thread gets delayed to finish
- some self.namespace.shell.user_ns vars disappear, so do a safe delete
- expose/document more of `ipyexperiments.utils.mem` helper functions