Get rid of warnings/errors spam in build

[dcolligan]

Issue #780

[dcolligan]

@david4096 If one wants to see errors / warnings from the sphinx build, can't one just turn them back on? Errors and warnings are no good if everyone habitually ignores them.

[david4096]

Add a flag that makes it easy for the current logging to happen to change the default. I think straight passing down the arguments to make docs might be fastest/easiest, but if you want to add a verbose key, no argument here.

[dcolligan]

@david4096 flag added. Get the warning output by doing: make docs verbose=true

[david4096]

Thanks, we don't deserve to take credit for all those warnings when we're trying to parse other people's comments :).