- added unit testing into automated unit testing processes

- Finished preliminary implementation of Emulated Driver
- Emulated Driver uses APScheduler to emulate subscriptions
- Implemented basic unitary testing for Device Driver API
- Still pending to integrate Driver API within Device service

- Implemented GetConfig/SetConfig/DeleteConfig
- Implemented unit tests for GetConfig/SetConfig/DeleteConfig
- Implementing simple DiscriteEventSimulator to emulate monitoring
- Remains to implement SubscribeState/UnsubscribeState/GetState
- Remains to implement unit tests for SubscribeState/UnsubscribeState/GetState

This commit is just a backup.

- Added REST API Server to Compute component
- Factorized get settings from environment variabes into common method get_setting

Common / Context / Device / Service:
- Improvements in unitary testing
- Extended assertion validators tor testing
- Factorized service implementation code to improve testability, reusability and increase code coverage

Factorization of code between services and minor unitary testing improvements. (Not finished, it is just a backup)

Common:
- Improvements in Database API definition and unit tests
- Implemented additional Assertions to be used by unitary tests

Context and Device:
- Improved logging of errors.

Service:
- Implemented service methods (except GetConnectionList). All methods are under active debug.
- Partially implemented unitary tests

Common:
- reorganized Database API to enable extension of Context API with entities (e.g. Service)
- solved minor bugs in Database API

Context and Device services:
- rearranged services and unit tests according to mentioned Context API changes

Service service:
- initial release (under development, this is just a backup of code)

Common:
- renamed report_coverage.sh script to report_coverage_all.sh

Common/DatabaseAPI:
- improved root class validations and test units
- added _RootEntity interface
- improved definition of Context database API entities

Context service:
- added AddLink/DeleteLink rpc methods
- temporarily disabled integration tests

Device service:
- applied renamings in service and test units

Common:
- implemented ServiceException class
- updated attributes in entities belonging to Database API
- implemented test method to populate database with example topology

Context service:
- updated genproto script
- implemented report_coverage_context script
- moved specific rest scripts to root folder
- minor arrangements in ContextClient
- updated proto python files
- implemented GetTopology RPC functionality
- implemented unitary testing for GetTopology

Device service:
- updated genproto script