Some updates to docs

Fixes #48.
add manager application
fix condition structure in http_server_request function
add commands to worker application
add manager module in server, begin to implement a new worker management
managers are in server's config file; workers test suite works
implement a first scheduling for manager, add config files in manager and server
fix jobs launcher
fix job_name field in server; try to fix kill management in worker
fix job status management; add lock in workers; add busy status to workers
Merge pull request #56 from msimoncz/dev

Added a new component, the manager, as agreed in a previous design session. This core functionality allows to a server to communicate with multiple clusters of workers.