* fix: elements would lose some state like scroll position because of "virtual parent" optimization
* refactor: the bugfix code
bug: elements would lose some state like scroll position because of "virtual parent" optimization
* fix: an error occured at applyMutation(remove nodes part)
error message:
Uncaught (in promise) DOMException: Failed to execute 'removeChild' on 'Node': The node to be removed is not a child of this node
- What was broken was that it would just play activity from the first page view, but then would stop at the second page view (meta) as actions after that had been discarded
- This restores the functionality given by the comment 'return the events from last meta to the end.' - we never want to discard events that are after the baseline time
- I believe 'session' is the incorrect terminology for this function name, as a session in web analytics usually means a series of page views
* introduce pako and add general packer interface
* add tests for packer
* use function API instead of class API for better tree shaking support
* refcatoring the rollup bundle config
1. add a liveMode flag to config, when liveMode is set, the timer
will keep running even though all the actions casted
2. add a public method addEvent, which will cast newly added event
in sync
3. move mouse in sync mode with the latest position info
