* fix dist transpile with memopt

* update api.spec

* polish dist transpile api

* update apispec

* update apispec

* refine dist train RPC deps

* clean up

* clean up

* fix ut

* remove input for fetch_barrier

* follow comments

* dist transpiler add control dependency var between send and recv

* fix async deps

* follow comments and refine

* fix deps connect for rpc ops

Add dependency to send recv

* dist transpile can pass startup program by argument

* update API.spec

* hide misc APIs

* update

* fix transformer test

* update API.spec

* fix dist train with rmsprop

* add rmsprop transpiler test

* update by comment

Fix str and bytes problem
Fix sorted problem
Fix math problem
Fix CI problem

better test

* hide variable API

* edit API.spec

* remove block api

* remove clone_variable

* hide block inner apis

* update

* fix tests

* make transpiler test reliable

* add more

* follow comments

input vars will NOT take into account