Setup Lerna monorepo, splitting reporter to new package

[valscion]

This PR aims to get the build to pass. Part of version 3 upgrade, pointing to PR #97 and not master.

[valscion]

🎉 This works:

cd packages/webpack-bundle-analyzer-plugin
npm pack
mv webpack-bundle-analyzer-3.0.0-alpha.0.tgz /path/to/our/app/
cd /path/to/our/app
npm install ./webpack-bundle-analyzer-3.0.0-alpha.0.tgz

The package file used was this: https://github.com/th0r/webpack-bundle-analyzer/releases/download/v3.0.0-alpha.0/webpack-bundle-analyzer-3.0.0-alpha.0.tgz

webpack-bundle-analyzer@3.0.0-alpha.0 node_modules/webpack-bundle-analyzer
├── filesize@3.5.10
├── opener@1.4.3
├── commander@2.11.0
├── acorn@5.1.1
├── @webpack-bundle-analyzer/reporter-treemap@3.0.0-alpha.0
├── gzip-size@3.0.0 (duplexer@0.1.1)
├── ws@2.3.1 (ultron@1.1.0, safe-buffer@5.0.1)
├── chalk@1.1.3 (escape-string-regexp@1.0.5, ansi-styles@2.2.1, supports-color@2.0.0, strip-ansi@3.0.1, has-ansi@2.0.0)
├── mkdirp@0.5.1 (minimist@0.0.8)
├── express@4.15.3 (setprototypeof@1.0.3, escape-html@1.0.3, array-flatten@1.1.1, cookie-signature@1.0.6, utils-merge@1.0.0, encodeurl@1.0.1, merge-descriptors@1.0.1, content-type@1.0.2, methods@1.1.2, cookie@0.3.1, fresh@0.5.0, content-disposition@0.5.2, etag@1.8.0, parseurl@1.3.1, vary@1.1.1, range-parser@1.2.0, path-to-regexp@0.1.7, serve-static@1.12.3, statuses@1.3.1, depd@1.1.0, qs@6.4.0, on-finished@2.3.0, finalhandler@1.0.3, proxy-addr@1.1.4, debug@2.6.7, send@0.15.3, accepts@1.3.3, type-is@1.6.15)
├── ejs@2.5.6
└── lodash@4.17.4

And when I generate a performance build, it works!

Likewise, in this repository, after running npm run build in the root, I can check out whatever samples I've got from other PRs:

./packages/webpack-bundle-analyzer-plugin/lib/bin/analyzer.js samples/tmp/stats.json