Resolve "Get image metadata as dict"

Closes #49 (closed)

The returned app.metadata returns something like:

{
    "AREA_OR_POINT": "Area",
    "DataType": 1.0,
    "DriverLongName": "GeoTIFF",
    "DriverShortName": "GTiff",
    "GeoTransform": [
        760056.0,
        6.0,
        0.0,
        6946092.0,
        0.0,
        -6.0
    ],
    "LowerLeftCorner": [
        760056.0,
        6944268.0
    ],
    "LowerRightCorner": [
        761562.0,
        6944268.0
    ],
    "ProjectionRef": "PROJCS[\"RGF93 v1 / Lambert-93\",\n...AUTHORITY[\"EPSG\",\"2154\"]]",
    "ResolutionFactor": 0,
    "SubDatasetIndex": 0,
    "TIFFTAG_SOFTWARE": "CSinG - 13 SEPTEMBRE 2012",
    "TileHintX": 251.0,
    "TileHintY": 8.0,
    "UpperLeftCorner": [
        760056.0,
        6946092.0
    ],
    "UpperRightCorner": [
        761562.0,
        6946092.0
    ]
}

pyotb/core.py

@@ -62,11 +62,14 @@ class OTBObject(ABC):
         mdd = dict(self.app.GetMetadataDictionary(self.output_image_key))
         new_mdd = {}
         for key, val in mdd.items():
-            splits = val.split("=")
-            if key.lower().startswith("metadata_") and len(splits) == 2:
-                new_mdd[splits[0].strip()] = splits[1].strip()
-            else:
-                new_mdd[key] = val
+            new_key = key
+            new_val = val
+            if isinstance(val, str):
+                splits = val.split("=")
+                if key.lower().startswith("metadata_") and len(splits) == 2:
+                    new_key = splits[0].strip()
+                    new_val = splits[1].strip()
+            new_mdd[new_key] = new_val
 
         return {
             **new_mdd,