Interfaces were handled globally before this commit. Now
alerts can be configured per-interface. So for example alerts
for the same host 193.168.2.1 can be handled differently on multiple interfaces.
Old alerts configured should be automatically migrated thanks to script startup.lua
This commits also paves the way to introduce stateful alerts in the professional version
Added .gitignore file for ignoring selected files
Reworked src and include paths to organize the source better
Fixed bug with invalid git version caused in some settings that do not compile code extracting it from github
