Rename InvalidToken exception to InvalidTokenError

...as discussed in jpadilla#60.

Author: wbolster-eiq

README.md

@@ -43,12 +43,12 @@ You can still get the payload by setting the `verify` argument to `False`.
 jwt.decode('someJWTstring', verify=False)
 ```
 
-The `decode()` function can raise other exceptions, e.g. for invalid issuer or audience (see below). All exceptions that signify that the token is invalid extend from the base `InvalidToken` exception class, so applications can use this approach to catch any issues relating to invalid tokens:
+The `decode()` function can raise other exceptions, e.g. for invalid issuer or audience (see below). All exceptions that signify that the token is invalid extend from the base `InvalidTokenError` exception class, so applications can use this approach to catch any issues relating to invalid tokens:
 
 ```python
 try:
     payload = jwt.decode('someJWTstring')
-exception jwt.InvalidToken:
+exception jwt.InvalidTokenError:
     pass  # do something sensible here, e.g. return HTTP 403 status code
 ```
 

jwt/__init__.py

@@ -28,28 +28,28 @@
 
 __version__ = '0.4.0'
 __all__ = [
-    'encode', 'decode', 'InvalidToken', 'DecodeError',
+    'encode', 'decode', 'InvalidTokenError', 'DecodeError',
     'ExpiredSignature', 'InvalidAudience', 'InvalidIssuer'
 ]
 
 
-class InvalidToken(Exception):
+class InvalidTokenError(Exception):
     pass
 
 
-class DecodeError(InvalidToken):
+class DecodeError(InvalidTokenError):
     pass
 
 
-class ExpiredSignature(InvalidToken):
+class ExpiredSignature(InvalidTokenError):
     pass
 
 
-class InvalidAudience(InvalidToken):
+class InvalidAudience(InvalidTokenError):
     pass
 
 
-class InvalidIssuer(InvalidToken):
+class InvalidIssuer(InvalidTokenError):
     pass