fix some bugs in polling system
Merge pull request #183 from projectcs13/sp7.sc3.fix_bugs_in_polling_system

fix some bugs in polling system
virtual stream as a gen_server
Made virtual streams as a gen_server and made a supervisior for them
Updated so that supervisor is started on startup and added function to initialize the virtual streams
made virtual stream process start on startup
Added functionality to add children under supervision
Merge pull request #185 from projectcs13/sp7.sc3.start_virtual_streams_when_starting_engine

Sp7.sc3.start virtual streams when starting engine