Fix to Json Boolean native constructor
Merge pull request #345 from i-e-b/master

Fix to Json Boolean native constructor
Fix "dropped" frames for text updates (#224, #339) using @timthelion's insights in #350

* Change the implementation of `notify` so that it does not have a
return value any more.

* Get rid of the only remaning use of the return value of `notify` in
the `every` function.

* Have a "lock" on each round to ensure that no library or runtime
calls `notify` synchronously, causing an update to happen half way
through another update, ultimately leading to a dropped frame.
Add error and explanation for infinite type aliases
Add an occurs check to finally resolve #294

Add it in the more clever location suggested by Pottier and Remy. Also
change the style of error messages to get rid of the expected/actual
problem for now, and make hints read more smoothly.
Fix minor indentation issue with `eightyCharLines`
Abstract out the code for markdown parsing, making it easier to switch out the implementation