Added simple overview/quick mention of protocol buffers

Some editing/rewriting of example, fixed links, etc.

grand unified hello world

Remove separate step now that all the content has been moved into the main doc

Remove separate step now that all the content has been moved into the main doc

Remove separate step now that all the content has been moved into the main doc

Remove separate step now everything's been moved into the main doc

Java: move java code to a subdir

Sync from master

Fixes the bullet points in the proto README.md

Adds the common protos along with a README.md

- Also specifies the what type of source is being rendered in the
  syntax-highlighted sections

Fix typos, grammar and broken link.