v0.2.1

Applied the following pull requests:

patch for selecting the unit system: bcbcarl#10
patch for url request to return ascii rather than html bcbcarl#18
patch to use https instead of http: bcbcarl#15
fixed various elisp linter errors (mostly docstring)

Also updated the default cities, and provided prompt text at the end of the forecast. Enjoy!

Full Changelog: v0.1.0...v0.2.1