[BDSDK-34] actual server response for invalid signature interpreted
correctly
[BDSDK-35] implemented data set loading
[BDSDK-37] merged report and data set attributes
[BDSDK-39] implemented tests for bulk upload data structure
[BDSDK-39] implemented sending CSV content and handling the response

Conflicts:
	src/com/belladati/sdk/impl/BellaDatiClient.java
[BDSDK-39] updated to send JSON instead of CSV
[BDSDK-39] implemented setting import column format
[BDSDK-39] implemented overwrite policies