Issue #64: using --config and yaml !include instead of --config-dir
*.conf -> *.yaml
Removed const.RULES_DIR and const.CONFIG_FILE
Comment about gns/api_.py
Removed const_site.py
Removed gns.const
Merge pull request #71 from mdevaev/issue-64-yaml-include

Issue #64: using --config and yaml !include instead of --config-dir