Karma should compile its static resources on the client if they're not present

[EzraBrooks]

Expected behaviour

The current 1.7.1 release on NPM does not work for my project. It entirely prevents us from running unit tests, as described in #2798. I was hoping I could just pull the repository as a git URL in NPM until the issue was fixed in a stable release.

Actual behaviour

However, when pulled from GitHub, the project is unbuilt and therefore unusable without running the build scripts. NPM has a post-install step for this reason. It is not sustainable for me to tell every member of my team to run your build scripts just because we have to workaround a fault in the current stable version.

Environment Details

• Karma version (output of karma --version): Irrelevant
• Relevant part of your karma.config.js file: Irrelevant

Steps to reproduce the behaviour

1. Pull the project from a git URL instead of from an npm registry
2. Try to run Karma
3. 404 on karma.js because it's not built.