Less 'his' in quote
Add exercise sandbox and solution files
Add script includes to exercises that need them
Add download link and more text to exercise page
Changed '\<=' to '<=' in Chapter 1
Fix export

I tried to use require('./ancestry.js'), but I was getting the following error:
.../ancestry.js:46
  module.exports = ancestry;
                   ^
ReferenceError: ancestry is not defined
More magic in sandbox code mangling to make using a fundecl before its definition work

Closes #64
Prevent editors from sticking out of window when growing
Merge remote-tracking branch 'upstream/master'