move .gcalclirc format to something standard (probably toml)

[jcrowgey]

gcalclirc has a bit of an awkward format.

pip, tox, other programs in the python ecosystem use toml for configuration files.

related #322 #381

[dbarnett]

+1, I had toml in mind as a good format as well.

[dbarnett]

I just merged #744 to implement the first bit of toml config. You can now create a config.toml file at some path like ~/.config/gcalcli/config.toml (see gcalcli --help for exact path used on your system) and configure default-calendars via that file:

#:schema https://raw.githubusercontent.com/insanum/gcalcli/HEAD/data/config-schema.json
[calendars]
default-calendars = ["Personal", "Work"]

From here it just needs to be filled in with more supported options and have the code cleaned up a bit.