Merge pull request #23 from orignal/master

Merge pull request from orignal/master
Merge pull request #24 from orignal/master

delete non-responding SSU sessions
Merge pull request #25 from orignal/master

don't send session request twice
some cleanup
some cleanup
GetIdentHash for LocalDestination
pass LocalDestination by reference
pools per ident hash
split AddressBook header/source
improve hosts.txt loading
Merge pull request #50 from cpubug/master

AddressBook
moved encryption keys from TunnelPool to StreamingDestination
generic SSU timer
exploratory pool added
move exploratory tunnels to separate pool
Adding initial travis file.
dummy change for triggering travis
Adding build status to README
fixed race condition
Merge branch 'master' of https://github.com/orignal/i2pd