RELEASE: Jump into v0.2.0
RELEASE: Jump into v0.2.0

- Add method `requestHandler` in `Query` to set the request Handler.
- Remove `flushAdd` method of `Client`.
- Remove buffering feature in the `add` method of `Client`

CondeNast/solr-node-client,yanxi-com/solr-node-client,lbdremy/solr-node-client,kfitzgerald/solr-node-client,tpphu/solr-node-client,chhams/solr-node-client,luketaverne/solr-node-client,nicolasembleton/solr-node-client,Bangsheng/solr-node-client,lbdremy/solr-node-client,godong9/solr-node-client