Implemented fast retransmit
- Send lost packet after receving 3 duplicate acknowledgements
Merge branch 'master' into flow

Conflicts:
	flow.py
Fixing fast retransmit
Bug fix for fast retransmit; add send packet timeout
[Flow] More fixes
Merge branch 'master' into flow
Refactored FAST go-back-n
Merge branch 'master' into flow
Fixes
Refactored Tahoe
Merge branch 'flow' of github.com:kexinrong/NetworkSimulator into flow
Fix alpha initialization for FAST
[Tahoe] enter slow start when receiving duplicate acknowledgements
WORKING VERSION
Merge pull request #30 from kexinrong/flow

Implemented fast retransmit