Resolve SAR metadata interfaces

Refactor image metadata interface for SAR sensors. The metadata are now read by gdal instead of ossim. Concerned sensors are :

• SAR IMI: TerraSar
• SAR IMI: CosmoSkyMed
• SAR IMI: Radarsat2

The metadata parsed are :

1. For CosmoSkyMed:

• AcquisitionStartTime
• AcquisitionStopTime
• Mission
• Mode
• ProductType
• SensorID
• Instrument
• RadarFrequency
• OrbitDirection
• OrbitNumber
• Polarization
• Swath
• PRF
• SAR Orbits geom

2. For TerraSar:

• AcquisitionStartTime
• AcquisitionStopTime
• Mission
• Mode
• ProductType
• SensorID
• RadarFrequency
• OrbitDirection
• OrbitNumber
• PRF
• PSF
• Polarization for each band
• LineSpacing
• PixelSpacing

3. For RadarSat2:

• AcquisitionStartTime
• Mission
• BeamMode
• ProductType
• Instrument
• SensorID
• RadarFrequency
• OrbitDirection
• PRF
• PSF
• CenterIncidenceAngle
• Polarization for each band
• ProductionDate
• LineSpacing
• PixelSpacing
• NumberOfLines
• NumberOfColumns
• AverageSceneHeight

Three tests have been added, one for each satellite (see ioTvImageMetadataInterfaceTest_Radarsat2, ioTvImageMetadataInterfaceTest_TerraSar and ioTvImageMetadataInterfaceTest_TerraSar).

Data/Baseline/OTB/Files/ioTvImageMetadataInterfaceTest_CosmoSkyMed.txt

+SensorID CSK
+Mission CSK
+Instrument CSKS3
+ProductType SCS_B
+Polarization HH
+Mode ENHANCED SPOTLIGHT
+Swath S1
+OrbitDirection DESCENDING
+TileHintX 128
+TileHintY 128
+DataType 1
+OrbitNumber 13415
+PRF 3321
+RadarFrequency 9.6e+09
+AcquisitionStartTime 2011-04-18T18:03:27.915976Z
+AcquisitionStopTime 2011-04-18T18:03:29.380925Z
+SAR <SARParam>