Start on the global problem class.

SimPEG/Exceptions.py

@@ -0,0 +1,13 @@
+
+
+class SimPEGException(Exception):
+
+    def __init__(self, reason=''):
+        self.reason = reason
+
+    def __str__(self):
+        return '%s: %s' %(self.__class__.__name__,  self.reason)
+
+
+class PairingException(SimPEGException):
+    pass