Update lunarphase with keyboard controls, add custom keyboard snippets

[doctorfree]

The lunarphase module has been updated with keyboard controls to view the next or previous day/week lunar phase, open a url in a browser, and enable/disable widget display. These changes have been submitted in a wtf pull request.

The documentation for these changes are included in this pull request.

Note that this pull request includes some new keyboard snippets. The keyboard controls in lunarphase want to use KeyUp, KeyDown, and CtrlD but these are dedicated to other functions and the help message cannot be customized. To provide customized messages for these keys I added new keyboard snippets. Also, only lower case letters were available but lunarphase enables 'N' and 'P' keys to display next week and previous week. So I added keyboard snippets for 'N' and 'P'.

If these new keyboard snippets are not suitable I can easily modify lunarphase to accommodate your preference.

Note also that the todo module seems to be looking for ctrlf.md when it should be ctrlF.md. This causes mkdocs to throw a non-fatal exception. A fix for that is not included in this pull request.