* remove 2.7 from CI and publishing
* fill out classifiers and also make it not be installed on 3.5
* some minor bumps so that the old deps work on python 3.5
Sometimes the build agents get lost or die (error codes -1 and 2). Retry automatically a maximum of 2 times if this happens.
Error code reference:
* -1: Agent was lost
* 0: Build successful
* 1: There was an error in your code
* 2: The build stopped abruptly
* 255: The build was cancelled
