refactor io "read"-type functions into a single function

[cpcloud]

there's a few of these floating around basically to dispatch on different kinds of possibly ambiguous string/filename/url input. would be nice if there was something in common or util that just does what you want. this may be overly optimistic...

[cpcloud]

grin 'def _read\(' yields:

./pandas/io/ga.py:
  268 :         def _read(start, result_size):
./pandas/io/html.py:
  109 : def _read(io):
./pandas/io/parsers.py:
  179 : def _read(filepath_or_buffer, kwds):
 1335 :             def _read():

i'm assuming there's another one for the upcoming shiny new read_json stuff...
cc @hayd @jreback

[jreback]

I just added io. common where I out some of this

@cpcloud feel free to refactor those types of things

[cpcloud]

i think i'll wait until the dust settles from clipboard/json things before handling this...

[jreback]

I think this is actually all done, except for #4084

[cpcloud]

should i close? i might've been thinking too general here. i want(ed) a context manager called read that would read anything (url, file, stringio [a no op there], etc) anything that could be "read" from. i'm not sure that's the best way to go tho without a massive function handling special cases...

[jreback]

yeh might as well
io/common pretty good and can be updated as needed with common functions

maybe need an issue to go thru and consolidate web access type functions
(I think there is an issue about using the request module out there to do that)

[cpcloud]

requests is niiice.

[jreback]

yup linked it (maybe add a todo at the top from my comments?)