* test: run in headless chrome
* chore: update travis node version
* chore: upgrade test deps
* test: fix tests
* test: support async await
* test: fix tree test case
* test: fix tree test cases
* test: fix popper test case
* input: simplify internal implementation
remove currentValue, strictly follow one-way data flow
hack for MSIE input event when placeholder is set
remove isKorean hack (#11665, #10648)
* input-number: fix for new el-input
* test: input, fix vue warning
* date-time-range: fix for new el-input
* pagination: fix for new el-input, simplify internals
* input: fix input event on compositionend
* input-number: fix for new el-input
* input-number: nuke userInput on change