"Conventions used in the compiler"

[nikomatsakis]

Some of this material exists already scattered about, and/or maybe this overlaps with the glossary, but I think it'd be helpful to try and capture some common conventions.

Here are some things I'm thinking about:

• How to format code (#47)
  • Um... kind of a mess. Hopefully we'll move to rustfmt.
• Naming conventions (maybe this should just be in the glossary, actually?)
  • the cx suffix -- short for "context"
  • 'tcx and 'gcx -- mostly direct elsewhere for detailed explanation?
• When to add/avoid adding dependencies from crates.io? What is the vetting process?
  • Whitelisting?
• What else?

[mark-i-m]

cc #47 (adds conventions.md)