More tweaks.

- aliases
  - `g` runs grunt
  - `gin` grep recurse insensitive line numbers
  - `gg` git grep
  - alias vim to `mvim -v` if possible
  - `jsc` JavaScript console.  Not perfect, but better than default node REPL at
    least.

- pws defaults
- `git cpr <n>` for checking out github pull request n.  Also fetch pull refs by
  default.
- `--decorate` all the git logs.