Make DebuggerStepThrough attributes consistent

... and add missing intellisense

Merge pull request App-vNext#394 from App-vNext/v570dev

Merge v5.7.0dev branch to master

Remove magic string from test collection specification

Merge development branch for v5.6.0

(intellisense correction)

Readme - add note for twitter notification (App-vNext#339)

Escape symbols in nuspec (App-vNext#291)

Add interface providing read-only access to a policy registry (App-vN…

…ext#283)

* Add interface providing read-only access to a policy registry

Adds an interface providing read-only access to a policy registry. Useful to prevent consumers changing policies in registry; for example to enforce separation of population of policy registry from usage.

* Add IReadOnlyPolicyRegistrySpecs

Merge pull request App-vNext#263 from reisenberger/v5.2.0

Add PolicyRegistry and interfaces to Polly (v5.2.0)

Merge pull request App-vNext#244 from reisenberger/reisenberger/featu…

…re/expandcontextusage

v5.1.0: Allow different parts of an execution to exchange state through `Context` flowing with execution