Remove history comments that aren't useful to users of webbit
Remove history comments that aren't useful to users of webbit

Only list API-relevant changes. Unit tests don't count. For those that
want all of the changes, the version diff is provided.

HuangYog/webbit,EricCen/webbit,lostdj/webbit,lostdj/webbit,EricCen/webbit,HuangYog/webbit,HuangYog/webbit,EricCen/webbit,lostdj/webbit,HuangYog/webbit,EricCen/webbit