Exchange calendar: fixes for the ICS writer.

- Now SimpleIcsWriter does the UTF-8 conversion, and folds lines according
  to the number of bytes in UTF-8.
- It now escapes special chars in TEXT values.  You can safely put , ; \ or
  line breaks. in summary, location, and description.
- Quotes all CN.  (leftover from Ibb8f155a)
- Replace "s in CN with 's (rather than removing them)

Bug 2508283
Bug 2515768

Change-Id: Ibdced53ee32bba950608d63f507b11b24eaad7b0
4 files changed