Create style guide for new content

[at055612]

We could do with a style guide in the readme to enforce a consistent style when it comes to the following:

• naming of feeds
• naming of other entities
• naming of folders
• naming of packs
• structure of a pack (in source form)
• structure of a pack (when viewed in stroom)
  etc.

Initial discussions agreed that a feed of squid events for a system called "My System" would become MY_SYSTEM-SQUID-EVENTS.
Also agreed that other entities and folder will be upper camel case with spaces.