ENH: Replacing remaining calls to CalculateNumberOfStreamingDivisions by calls to StreamingManager, which is the up-to-date way of doing streaming

ENH: Adding a new class to manage configuration parameters through environment variables and switch to default values if undefined

ENH: Removing old method to calculate streaming parameters in StreamingTraits, and removing useless base class

ENH: Replacing remaining calls to CalculateNumberOfStreamingDivisions by calls to StreamingManager, which is the up-to-date way of doing streaming

TEST: Removing useless test based on the ConfigFile third party, which will be removed in next commits

COMP: always build TileMapImageIO, and fix ioTvImageFileReaderServerNameHTTPTest to avoid a crash in GDAL<1.11