Add gitignore, remove binary stuff from repo

[akrherz]

This PR does the following

• adds a basic .gitignore so that common things in your source tree do not get auto-added to revision control when doing things like git add *. Binary stuff should generally not be included within source revision control.

• removes a bunch of binary artefacts / build stuff that should not be within source revision control.

• Stuff in /dist is ephemeral and should be uploaded to pypi / attached to github releases, if you wish.

• __pycache__ is local to your python install / environment

• same for sounderpy.egg-info

• docs/build are ephemeral as well

[kylejgillett]

Hi Daryl!

Thanks for doing this -- still pretty new to, and learning the do-and-dont's of source revision control. Ill get this merged in!