replace description lines that begin with '*' with '✱'

[christian-blades-cb]

this is to address issues like #29 when event descriptions that include lines starting with * can break gcal synchronization

[christian-blades-cb]

Essentially #55, but a bit more specific about when to replace the asterisk.

[telotortium]

Hi everyone! This repository is obsolete - the actively developed fork is now https://github.com/kidd/org-gcal.el, which is also the "org-gcal.el" on MELPA (see #115). I'm one of the maintainers of https://github.com/kidd/org-gcal.el. I can't directly close issues or PRs on this repo, but please download https://github.com/kidd/org-gcal.el and see if your issue or PR is still applicable. If so, open an issue or PR on https://github.com/kidd/org-gcal.el. In any case, you should close your issue or PR in this repo.