loquat: loquat v2.0.0-M7

Data mappings:

• #45: Changed DataMappings remoteInput/Output from records to simple Maps
• Added an option to the config to switch on/off input objects existence check
• #44: Renamed DataMapping's id to label
• #47: Added a logger message and some kind of progress output for the input objects existence check
• #50: Instead of checking input objects object metadata, listing objects with the given prefix
• #52: Added a check for missing/non-needed input/output data keys in the datamappings

Data processing:

• #51: Fixed input objects handling by passing the map of (dataKey.label -> fileLocation) from worker to the processing context; this way context.inputFile lookup doesn't rely on conventions and return the actual file location

Self-termination:

• #48: Added a time deadline for SQS polling
• Added some logging and exception handling to the polling

Other fixes:

• #49: Removed any worker instance state tagging for now; was causing RequestLimitExceeded on a big autoscaling group with quick tasks
• #43: Changed log messages for downloads/uploads