Update Connectors over REST
Most important additions:
- Made REST work with Update Connectors; added a Connection::sendData() for this.
- Added Helper::normalizeDataToSend() which can take as input (mostly) the same arrays as Helper::constructXML() does. Its output can be used in Connection::sendData(), which means that update functionality is also (mostly) 'portable' between SOAP and REST clients, when using these arrays as input. Not all updates work yet / are tested well, though; see README.md#Bugs.
- Now recognizing parameter for 'ordering' results of SOAP Get Connectors. (I didn't know this existed before.) Connection::getData() now recognizes/uses the 'OrderByFieldIds' argument (which is native to REST calls) also with SOAP clients. (SOAP calls' own 'Index' option now works through Connection::getData() calls too, but it is not recommended to use this because of its fairly obscure syntax.)
- Added Helper::getDataBatch() to assist in fetching multi-batch data sets.