Fix for reading in old mesaplot v1 pickle files.

Add notes that people should not depend on this working between versions
and for long term storage, history and profile files should be kept.

README.md

@@ -52,6 +52,7 @@ m=mp.MESA()
 
 Now m contains all the useful stuff
 
+
 ### History files
 ````python
 m.loadHistory()

mesaPlot/file_reader.py

@@ -204,7 +204,8 @@ def __getitem__(self, key):
             if key in self.data.dtype.names:
                 return self.data[key]
             if key in self.head.dtype.names:
-                return self.head[key][0]
+                return np.atleast_1d(self.head[key])[0]
+
 
         try:
             return self.__dict__[key]
@@ -254,26 +255,35 @@ def _loadPickle(self, pickname, filename):
             # Get checksum
             filehash = _hash(filename)
             try:
-                pickhash = pickle.load(f)
-            except:
+                version = pickle.load(f)
+            except Exception:
                 raise ValueError("Pickle file corrupted please delete it and try again")
-            if len(str(pickhash)) == len(str(_PICKLE_VERSION)):
-                if int(pickhash) != int(_PICKLE_VERSION):
-                    # Not a hash but a version number/ or wrong version number:
-                    return False
 
-            try:
+            # For mesaplot 1.* this is a hash, while 2.* is a version number
+            if len(str(version)) > 12:
+                # Version 1.0 hash
+                pickhash = version
+            else:
+                if int(version) != int(_PICKLE_VERSION):
+                    raise ValueError("Pickle file not recongised please delete it and try again")
+
                 pickhash = pickle.load(f)
-            except TypeError:
-                return False
 
             if (
                 os.path.exists(filename) and pickhash == filehash
             ) or not os.path.exists(filename):
                 # Data has not changed
                 # Get Data
-                self.data = pickle.load(f)
-                self.head = pickle.load(f)
+                data = pickle.load(f)
+
+                try:
+                    head = pickle.load(f)
+                    self.head = head
+                    self.data = data
+                except EOFError: # Handle 1.* verisons of pickle files
+                    self.data = data.data
+                    self.head = data.head
+
                 self._loaded = True
                 return True
         return False