Add solc package

[Georgi87]

The package.json does not list “solc” package, although it is required to run “truffle test”

[danfinlay]

I wasn't able to build for a while b/c my solidity was too new, so the workaround was:

npm uninstall -g truffle && npm install -g truffle@byoc

And then adding these lines to truffle.js:

module.exports = {
  ...
  compiler: {
    solc: "0.4.19"
  }
  ...
}

Then running npm i again, and I was able to truffle compile fine.