Enable running interop tests with dotnet CLI + CoreCLR

Add shutdown hook for CoreCLR

The public headers already have extern C

Exclude sweep tests from the "full" suite

Use a # of total outstanding requests to drive benchmark config

Grand unified closures

Update README.md

Fix typo in node.js README

Dotnet CLI distrib tests and associated cleanup.

Enable Mac OS X 10.6 compilation

PHP: update param description of function

Instead of specifying # of outstanding requests/channel, specify a total
outstanding size, and try to fit that to the number of channels.

add cacheable option to client_context

Manual upmerge from 1.0.x to master.

Add missing flag option

Change permissions to run on Jenkins.

add more known failure msgs.

Fix file mode

Add a script to run performance sweeps