Add the capability to load gunicorn.base.Application without the loading
of the arguments of the command line.
Add an example for the gunicorn.app.base.BaseApplication
Add an example of a standalone app
Start the documentation for the BaseApplication class
Work In Progress: Move the custom application section to a specific file and add it into the TOC
Merge pull request #736 from matrixise/feature/651

Feature/651
Merge pull request #727 from benoitc/feature/651

PR that rebase #651. Should also fix #625.

Add the capability to load gunicorn.base.Application without the
loading of the arguments of the command line.
Do not swallow unexpected errors when reaping

I can't imagine this wasn't what was intended here. Might be a merge
artifact but I can't trace it.

Thanks to Antti Kaihola (@akaihola) for spotting this.

Close #733