Add backpressure buffer for Janet pipline (#61)

Merge pull request #55 from techery/fix/double_subscribe_call_on_send

Fix wrong scheduler for ActionPipe's send

Add JanetActionException with an action inside for using ActionStateT…

…oActionTransformer. (#53)

Merge pull request #51 from techery/wrapper-callback-intercepting

Fix double error intercepting

Merge pull request #50 from techery/wrapper-callback-intercepting

Add result intercepting for ActionServiceWrapper's methods

Prepare 0.2.4

Prepare 0.2.3

Add MockHttpActionService

Also readme file was updated