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

Add sync variants of important tests, add sweeps across different channel counts

Remove blah repos from the visualization

Increase log verbosity for benchmark driver

Support >16kib frame sizes in core

Improvements to CoreCLR support

Fix fuzzing detected failure

List undocumented things in core, c++

update and add new generate_protos script in csharp examples

update nuget client to latest version on performance workers

Percent encoding routines

change hint paths for protobuf to use net45 dir in csproj files