Switch the project to be 0.9.2-dev

__version__ strings changed to 0.9.2-dev and update ChangeLog.md to make
space for 0.9.3.

__status__ strings were not changed as those remained untouched on the
0.9.1 -> 0.9.2 transition.
Merge pull request #206 from ElDeveloper/switch_to_0.9.2-dev

Switch the project to be 0.9.2-dev