First step towards an IDS

- IDS rules are split into concatenated OTP application:
- currently available OTP applications: 
    * epcap_app - provides packages (UDP, TCP, ..) from epcap_nif
    * content_app - parses text content
    * currently packages are piped as: epcap->content
    * as soon as e.g. an http_app becomes available, data might be piped as following: epcap->http->content
- rules can be activated and deactivated individually step by step upon demand without disruption
- works with Erlang observer application, which is available from Release 16B. (observer:start())