jspm.config.js not found if in a subdirectory

[kwesterfeld]

For whatever historical reason I cannot remember, my project's jspm.config.js location is in a source subfolder. When this occurs, the systemjs serve configuration sniffer can't find it.

I was able to workaround this by using manual builder configuration, but it would be really nice to have this work out-of-the-box.

  builder: {
    configFiles: ['smc/jspm.config.js'],