adds coverage reporting using nyc bin

[bcoe]

This pull request adds coverage reporting using nyc:

• run npm run coverage to get a human readable coverage report.
• run npm run coverage -- --reporter=lcov to get an HTML report over coverage in the /coverage folder.

Here's what the output looks like:

--------------------|-----------|-----------|-----------|-----------|
File                |   % Stmts |% Branches |   % Funcs |   % Lines |
--------------------|-----------|-----------|-----------|-----------|
   ./               |     82.34 |     75.97 |        80 |     82.52 |
      index.js      |     82.77 |     76.42 |     81.01 |     82.72 |
      test-unref.js |     54.55 |        50 |         0 |     66.67 |
   ./lib/           |     79.07 |        70 |     85.71 |     79.07 |
      commands.js   |       100 |       100 |       100 |       100 |
      queue.js      |     74.19 |        70 |     83.33 |     74.19 |
      to_array.js   |       100 |       100 |       100 |       100 |
      util.js       |        80 |       100 |       100 |        80 |
   ./lib/parser/    |     78.26 |     72.62 |        75 |     78.26 |
      hiredis.js    |         8 |         0 |         0 |         8 |
      javascript.js |     89.31 |     82.43 |     92.31 |     89.31 |
--------------------|-----------|-----------|-----------|-----------|
All files           |      81.4 |     75.36 |     79.61 |     81.53 |
--------------------|-----------|-----------|-----------|-----------|

[bcoe]

@raydog @brycebaril any objection to my updating this to a recent version of nyc, and adding coverage reporting to node_redis?

[raydog]

👍 This is cool. I actually didn't know about nyc. I always just used istanbul directly...