Set default calendar side to "left" from v4

[maread99]

Currently the default side for 24-hour calendars is "right" and for all others it's "both" (24 hour calendar's can't have side as "both").

When the side option was introduced these defaults were set to maintain existing behaviour.

With v4 I'd like to take the opportunity to make the default the same for all calendars and set it to "left" (which I think is the most intuitive option - a session open is a minute of the session, a session close is not).

@gerrymanoim, any objections? Anyone else?

[maread99]

Incorporated to PR #191.