Change web3 to fixed version 0.19.1

Merge pull request Consensys#150 from ConsenSys/bignum_dependency

Remove bignumber dependency. Temporary fix for broken web3.

Update RELEASE-NOTES & dist files. Tag release.

Rebuild dist files.

Fixed a bug that caused the dist files to fail in browsers

Update dist files.

Add test, update Release notes.

Merge pull request Consensys#110 from ConsenSys/buffer_bug

Fixes Firefox 48+ issues

Update README.

Add release note for v2.4.2