v0.6.2

• [+] utils more powerful， add objToParams、paramsToObj、getPageHeight、getScreenHeight new functions, More you can see utils/index.js.
• [!] Fixed the bug about wxc-ep-slider when only two sliders [pull/248].(#248)
• [!] Fixed the bug about wxc-searchbar when setting up custom styles and background conflicts at the same time issues/242/pull/245
• [+] wxc-mask Supports top param to control height at the top of the distance. issues/240/pull/241
• [!] Fixed the demo bug about wxc-popover pull/236