Merge branch 'features/initenv'
Fix bug of always generating same five peer-ids and pg_delays
Fix segmentation fault
Add counter for showing info of each piece was retrieve by how many peers
Merge branch 'features/event' of https://github.com/ChuKuanYu/BTTE into features/event
Fix syntax error of init script
Fix typo
Add execute permission
Change enum to enum class
Add function for generate exponential random number
Uppercase the enum attribute
Add event-driven related code (not complete yet)
Add pid data for event strcut
Add global var for knowing all pieces are retrieve or not
Implmenting event handler. Need to fix the bug of peer selection which invoke from event and the bug of infinite loop which iterate event_list
Fix bug of index for event
Move prefix underscore of variable names to tail for all private members
Use C++ RAND_MAX macro
Change trans_time in struct PeerLevel to bandwidth
Make pointers ref to nullptr after object were deleted