pd.to_datetime docstring needs upgrade
#### Problem description

`pd.to_datetime` has a [very short non-descriptive docstring](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.to_datetime.html):  `Convert argument to datetime`.

Using the term datetime is horribly confusing as there is a Python datetime, a NumPy datetime64 and a pandas Timestamp. Although, there is better documentation under the parameters, this needs to be expanded to more than 4 words.

#### Expected Output

Along with a more thorough explanation, It would be nice if there was consistency with how pandas refers to the triple-headed monster, datetime, datetime64 and Timestamp.