Update Pandas Parser to add more read functions

[sgoldenCS]

Currently the PandasParser only allows for the following file_formats:

• csv
• feather
• json
• pickle

A trivial improvement would be to add other functions that are already supported by Pandas including:

• html
• excel
• fwf
• table
• sql
• clipboard
• parquet
• orc
• xml
• stata
• sas
• spss

It might not be worthwhile to include all of them, but some might be more useful than others (excel, parquet, xml?).

Additionally, I think we could write a custom function that reads numpy files that would look something like the following:

def read_numpy(path, **kwargs):
    data = np.load(path)
    return pd.DataFrame(data, **kwargs)

The current structure of the PandasParser should allow any simple function that returns a pd.DataFrame to be used with only minor modifications to the parser module. This saves the work of re-writing an entire parser module that outputs a Pandas DataFrame for a new file format.