fix(custom series): the hover style should be always set but should not cache in hover state, otherwise the previous cache will be not reset and the previous hover style will remain; fix #11103.

Fix tree root node disappear  after roam.

fix(tree): fix root node disappear after roam in vertical orient and add roam test in the tree example

* test: Run the tests automatically for visual regression test.

* doc: Update CONTRIBUTING doc for test section

* test: Improve visual regression test UI

* test: Add tests select and run control in dashboard

* test: Use child process to run test. Add logs in dashboard

* test: Fix some logic issue of controlling test in dashboard.

* test(autorun): Improve Dashboard UI

* test: Remove puppeteer from devDependencies

* Update package-lock.json

* style: fix code style.

Update legend selector default option

Update links to documentation

Feature - Support version 3.0 (bmap)

Expanding echart to support version 3.0 (bmap) of Baidu Map API.

fix syntax error in readme about the paper