fix(init): clean the terminal if killed

Before, when user terminates `karma init` during answering a question, the terminal would stay colored.
feat(init): install missing plugins (frameworks, launchers)
feat(init): add nodeunit, nunit frameworks
feat(init): install karma-coffee-preprocessor
style(init): reformat the config templates
refactor(init): nothing super exciting
chore(init): add some TODOs
feat(config): remove default preprocessors (coffee, html2js)

This should have been done in e033d56.

We don't ship any plugin with Karma anymore.
Users should rather use `karma init`, which installs plugins for them.