chore: remove log4js install hack

Since 0.6.3, log4js works on both 0.8 and 0.10 so we don't have to do this hack anymore...
https://github.com/nomiddlename/log4js-node/issues/129
feat: allow inlined plugins

plugins = [
  'npm-module-plugin', {
  'launcher:inlinedLauncher': ['factory', ...]
];
fix: better error reporting when loading plugins
chore: update contributors
chore: release v0.9.2