enable state restoration

[zhongwuzw]

enable state restoration

[Kapeli]

Looks good. One issue: the webView's page gets reverted back to the "This page intentionally left blank" page upon restore.

[zhongwuzw]

@Kapeli , I fix the webView issue.

[Kapeli]

More issues on iPad:

1. Have Settings > Download Docsets open and quit and restore state, the download docsets view on the right isn't restored
2. If you have the split view collapsed (i.e. webView on whole screen) and quit and restore state, the split view is correctly restored, but the collapse button isn't restored in its right state so it tries to collapse the split view when you first tap it
   2.1. For some reason restoring with the split view collapsed causes the table views to appear below the search field
3. The selected row of table views isn't restored

[zhongwuzw]

@Kapeli I fixed issues on iPad. for the second issue, I think it's UISearchDisplayController bugs, so my solution is to force non-collapsed when state restoration.

[Kapeli]

More issues:

1. Doesn't work with Remotes
2. Issue 1 from enable state restoration #18 (comment) is still present on iPhone 6/7 Plus in landscape mode

[zhongwuzw]

@Kapeli , I updated codes to fix the issue.

[Kapeli]

Awesome job. Thank you! 👍