This is a bug included when richText is added

(1) provide detailed API to set hover style.
(2) enable to remove hover style.
(3) tweak the default text style setting.
(4) fix the conflict between hover and API emphasis for Symbol.

Enhance dataZoom: do not trigger if range not changed, otherwise cause bad effect when progressive rendering.

Tweak ordinal collection in dataset when value is number like year, which is expected to be category value but not index.

support dimension reference in label formatter.

(2) fix map and pie in dataset.

Fix encode.

(2) Support category collection for category axis.