Refactor restli-client request builder classes:
  1) deprecate header(), param and reqParam()
  2) add setHeader(), setHeaders(), addHeader(), setParam(), setReqParam(), addParam() and addReqParam()
For query parameter and action parameter that is array type, add convenient request builder method to add element one by one.
For ActionRequestBuilder, required parameter will call reqParam() instead of param() now.

RB=212287
BUGS=SI-981
R=adubman,jbetz,slim,sihde,si-dev