Moved exception type definitions to Errors.py.
Moved exception type definitions to Errors.py.

Renamed exceptions from *Exception to *Error.

Derived both exceptions from common base class called 'Error'.


git-svn-id: a9b3423f80f97d8686891a9c593c60a3eca95014@203 67c13c2a-ce2d-4362-9fbd-a73952e22801

keszybz/gnuplot-py