http://github.com/ -> https://github.com/
fix typos
update 'update-transaction' option
update trema 4a4dd1e81ac239def5fe601d1a494c0cd2f262da
fix typo
add vagrant example.

running virtual-network-platform on vagrant
update vagrant files
replace Open3 with systemu
added exception class
Merge remote-tracking branch 'origin/feature/systemu' into feature/systemu