Escape Markdown; avoid comment reordering; avoid abort on bad chars.

These are 4 general changes I needed in order to migrate my two GoogleCode issue trackers to GitHub which may be useful to others.

The Markdown escaping was critical to make the issue text readable on GitHub.

Perhaps you have a better solution in mind than my 5 second delay here, but comment reordering was a significant problem in my migration: 1 in 3 comments ended up out of order due to network reordering as they were fired off too quickly with respect to each other.  The 5 seconds may be overkill, and it does slow down the migration, but it worked and avoided all reordering.