* add -linear-schedule-with-warmup

* update lr scheduler usage in run_glue

* add import info

* add other 5 scheduler with warmup

* add copyright, update usage in run_glue

* simplify argument, make warmup arg support float and int

* Add some LambdaDecay scheduler with warmup, update usage in run_glue

* update classname and unify two cosine decays into one

* update usage in run_glue

* fix typo

* update WarmUp to Warmup, and update class name about Const, and update doc, and usage

* update usage of decay class

* update usage of decay class

* Unified the task name with paddle1.8

* fixed bug.