added _complex to suffix if the data is complex
#39 solved for mapper_radarsat2. #40 solved by adding SourceTransferType (from src) to options list in create_band method in vrt.py and update in mapper_radarsat2. Other mappers potentially retrieving complex data or mappers where the dst data type is different from the src data type should be updated accordingly.
Merge branch 'issue39' into develop