Update plugin-combo.js

combo后的url长度超过2000后不是直接抛错误，而是用对半拆分的方式拆成多个url，场景更加通用
Little improvement
Merge pull request #610 from lianqin7/patch-1

Merge plugin-combo.js to support 2000 characters above
Merge branch 'master' of github.com:seajs/seajs
Rebuild packages
Improve plugin combo and add test specs. close #610
Fix a bug in test spec
support publish test event
support publish test event
add event publish
fix style
Merge pull request #624 from leoner/master

增加测试运行过程中测试状态发布
Refactor util-request.js
Rebuild packages
Merge branch 'master' of github.com:seajs/seajs
Merge branch 'gh-pages' of github.com:seajs/seajs into gh-pages