* Make block class optional

* Fix test by removing unexpected space space

Fix progress bar height

* reuse serialized nodes ids

With this patch, each DOM node keeps its id during its existence. This
allows to apply RRWeb events to previous snapshots if needed.

`resetId` has been removed because it loses its meaning: calling it
would not reset the existing nodes ids anymore, only the new ones.

Since we don't reset the id anymore, we may exhaust the available ids
quicker, but Number.MAX_SAFE_INTEGER (2 ** 53 - 1) is pretty large, so I
doubt this'll cause any problem.

* improv TS typing

The `nAsINode` variable was not very elegant.  Simplify this by removing
the cast, and make the INode interface compatible with Node.

* update typings

…index.ts (#6)

Previously we use a regexp to match all the CSS selectors and add
our hover class name to it, which has been proved not solid and
may be very slow in some situation.
Using a production ready css parser can handle this better and also
provide ability's to do more accurate things to the recorded
stylesheets.

Broken CSS inside a page will throw an error on our behalf. This should
be ignored because we are not in control of the CSS on the page we are
recording.

* added src set as a parsed attribute

* added tests

* changed to /a

* added multiple attribute handling

* added better comment

* made snapshot ignore invalid input as if it is invalid input in the original DOM, it should stay invalid in the recreated DOM

* added extra absolute test case

* code style

* addressed comments

* Add canvas image content support

* use rr_dataURL as the key so we know its a rrweb-added attribute.

* fix canvas rr_dataURL rebuild

* added cssText check

* added testing

* Failing test

* Allow numbers in el name tests

* Allow numbers in el names

…messages in Chrome which are not exceptions (but look like them): (#30)

'Blocked script execution in '<page>' because the document's frame is sandboxed and the 'allow-scripts' permission is not set'