Crushlib

- Bug: Hammer and Jewel tunables profiles were not using straw2

- Feature: Support for Jewel profile tunables
- Bug: Fixed crash when trying to print CRUSH map with no devices

- Bug: Multiple 'set' steps in a rule were being considered
invalid syntax despite being common for erasure-coding

- Bug: Buckets would not be printed in reverse hierarchy
order, causing compilation errors.

- Bug: `crushlib.crushmap` was not being packaged

Initial pre-release with limited functionality.

- Abstraction layer for manipulating CRUSH maps.
- Tested with Python 2.7 and Python 3.6
- Support for reading pre-Luminous CRUSH maps
(device classes NOT supported)
- Basic manipulation available:
- Rename buckets
- Manipulate types (Add/Rename/Remove)
- Insert new buckets, move buckets
- Change root of a rule