chore: fix 4 of 5 peer dependency warnings by updating dependencies

[sschmidTU]

This is a PR for PR #384.
It fixes 4 of the 5 npm warnings for npm install that tell you to install peer dependencies.

The remaining warning seems unsolvable right now, because we also need a newer version of webpack:

npm WARN karma-webpack@3.0.4 requires a peer of webpack@^2.0.0 || ^3.0.0 but none is installed.
You must install peer dependencies yourself.

karma-webpack upgrades the webpack dependency in 4.0.0, but there's only a release candidate for that right now.

for tsify's dependency on browserify, i had to add browserify to the devDependencies. It's not ideal, because tsify might change that peer dependency in the future and then we can remove browserify as a dependency. But better than a warning, i think.

everything seems to work fine with this (npm install, karma tests, npm start, demo).

[bneumann]

Looks good. @sebastian we need browserify?

[sschmidTU]

We need browserify as a peer dependency for tsify. i wrote about it above. i think tsify won't abandon browserify so soon, so it's a decent tradeoff to add it i think.

edit: since tsify is a browserify plugin and we don't use it anymore, we don't need either of them. removed these dev dependencies.
see #103 for move from browserify to Webpack