BUG: to_sql with sqlite fallback rewrites table scheme even with if_exists='append'
From SO: http://stackoverflow.com/questions/24064509/to-sql-pandas-method-changes-the-scheme-of-sqlite-tables

The reason is that `get_table` is not implemented for fallback mode (https://github.com/pydata/pandas/blob/master/pandas/io/sql.py#L1072), so a `create_table_statement` is always called (https://github.com/pydata/pandas/blob/master/pandas/io/sql.py#L525).

Should look at it further to see if this is solvable, or a restriction of sqlite fallback.
