Backup: Refactores Transport::ConnectToBootstrapEndpoint

A bit
Adds OnConnect functor to Connection class
Backup: AddConnection is now called from OnConnect handler
Connection on_connect handler gets called even if connection fails

With an error as a parameter.
Cleaning up debug output
A bit more cleanup
Merge pull request #35 from inetic/MAID-286-Assertion_inside_ConnectToBootstrapEndpoint

Maid 286 assertion inside connect to bootstrap endpoint