Use project package.json to load additional plugins

[IAmJulianAcosta]

This fixes #12

[ivanvanderbyl]

Thanks for the PR @IAmJulianAcosta, I'll take a look at this soon.

[mwisner]

I'm just getting into but I needed a couple of non-standard d3 packages included and gave this a shot.

Unfortunately it didn't seem to work... I will poke around more as this seems like a far easier solution than making individual shim packages for every addon....

Error: ENOENT: no such file or directory, open '/app/tmp/source_map_concat-input_base_path-1GHW9ki2.tmp/vendor/d3-flame-graph/d3-flame-graph.js'
    at Object.fs.openSync (fs.js:653:18)
    at Object.fs.readFileSync (fs.js:554:33)
    at SourceMap.addFile (/app/node_modules/fast-sourcemap-concat/lib/source-map.js:75:31)
    at /app/node_modules/broccoli-concat/concat.js:200:16
    at Array.forEach (<anonymous>)
    at Concat.<anonymous> (/app/node_modules/broccoli-concat/concat.js:198:24)
    at /app/node_modules/fast-sourcemap-concat/lib/source-map.js:419:12
    at initializePromise (/app/node_modules/rsvp/dist/rsvp.js:567:5)
    at new Promise (/app/node_modules/rsvp/dist/rsvp.js:1039:33)
    at SourceMap.end (/app/node_modules/fast-sourcemap-concat/lib/source-map.js:406:10)

The broccoli plugin was instantiated at:
    at BroccoliMergeTrees.Plugin (/app/node_modules/broccoli-plugin/index.js:7:31)
    at new BroccoliMergeTrees (/app/node_modules/ember-cli/node_modules/broccoli-merge-trees/index.js:16:10)
    at Function.BroccoliMergeTrees [as _upstreamMergeTrees] (/app/node_modules/ember-cli/node_modules/broccoli-merge-trees/index.js:10:53)
    at mergeTrees (/app/node_modules/ember-cli/lib/broccoli/merge-trees.js:85:33)
    at EmberApp._mergeTrees (/app/node_modules/ember-cli/lib/broccoli/ember-app.js:1832:12)
    at EmberApp.javascript (/app/node_modules/ember-cli/lib/broccoli/ember-app.js:1307:17)
    at EmberApp.toArray (/app/node_modules/ember-cli/lib/broccoli/ember-app.js:1689:12)
    at EmberApp.toTree (/app/node_modules/ember-cli/lib/broccoli/ember-app.js:1711:38)
    at module.exports (/app/ember-cli-build.js:49:14)
    at Builder.setupBroccoliBuilder (/app/node_modules/ember-cli/lib/models/builder.js:56:19)

[ivanvanderbyl]

This should be taken care of in the latest beta, and soon 0.4.0, If that package name begins with d3- it will be loaded if it contains an AMD build.