Oracle fix

Cleaned up the code and added comments for the changes made to get the pokedex to work (as far as I can tell) with Oracle:
- table names are automatically shortened (vowels dropped) when the dialect is oracle, to fit the 30 character limit
- when using load/setup, long table names are used for the csv files, but short names are used for th table dropping/creation/insertions
- datatypes have been changed : Unicode(4000) breaks Oracle's rule on the size of NVARCHAR2 (max is 2000), so UnicodeText() is used instead (LONG data types)
- doctest updated to handle UnicodeText