Introducing Runtime layer (#41)

This commit contains the following changes:
- Add ask-sdk-runtime package
- Refactored following abstract and implemented classes from ask-sdk-core to ask-sdk-runtime, since they are generic
        - AbstractHandlerAdapter
        - HandlerAdapter (renamed to GenericHandlerAdapter)
        - AbstractRequestHandlerChain
        - RequestHandlerChain (renamed to GenericRequestHandlerChain)
        - AbstractRequestMapper
        - RequestMapper (renamed to GenericRequestMapper)
        - AbstractRequestDispatcher
        - RequestDispatcher (renamed to GenericRequestDispatcher)
        - AbstractExceptionMapper
        - ExceptionMapper (renamed to GenericExceptionMapper)
        - Dispatch, Skill Builder exceptions
        - User Agent utility
- Added AbstractSkillBuilder, AbstractSkill, RuntimeConfiguration classes
- Refactored dependencies as needed
- Refactored tests as needed

Author: nikhilym

ask-sdk-core/.coveragerc

@@ -6,4 +6,5 @@ include =
     ask_sdk_core/*
 exclude_lines =
     if typing.TYPE_CHECKING:
-    pass
+    pass
+    raise NotImplementedError

ask-sdk-core/ask_sdk_core/__version__.py

@@ -24,5 +24,6 @@
 __author_email__ = '[email protected]'
 __license__ = 'Apache 2.0'
 __keywords__ = ['ASK SDK', 'Alexa Skills Kit', 'Alexa', 'Core']
-__install_requires__ = ["six", "requests", "python_dateutil", "ask-sdk-model"]
+__install_requires__ = ["six", "requests", "python_dateutil",
+                        "ask-sdk-model", "ask-sdk-runtime"]
 

ask-sdk-core/ask_sdk_core/dispatch.py

@@ -21,7 +21,6 @@
 
 from .request_components import (
     AbstractRequestHandler, AbstractRequestInterceptor,
-    AbstractResponseInterceptor, HandlerAdapter, RequestMapper,
-    RequestHandlerChain)
+    AbstractResponseInterceptor)
 from .exception_components import (
-    AbstractExceptionHandler, ExceptionMapper)
+    AbstractExceptionHandler)