fix(0.8.4): fix performance problem in firefox

docs: update changelog

test: add test for v0.8.2

fix: 🐞 Fix bug of parser style error when using IE6 and 7 csshack

feat: fix bug of scopecss & peffect unit test

chore: change version

fix: 修复了hasOwnProperty和effect失效的问题

fix: 🐞 修复了在SSR环境下，抛出`Image is not defined`的报错问题

docs: update docs

docs: 更新文档