karma conf: prevent timeouts on Travis CI

[bajtos]

Increase the timeout values to prevent DISCONNECTED errors when
running the tests on slow machines (e.g. Travis CI).

[bajtos]

Here we go, Travis builds are green again 🎯

[bajtos]

For posterity, here is some info that helped me to solve this issue.

karma-runner/karma#598

I've noticed that using pre-processors can cause this to increase as well.
Since karma launches the browser then processes all the files. If your
preprocessors take a long time to run then I'll bet you see a direct
correlation.

codymikol/karma-webpack#8

I've solved the issue by increasing the browserNoActivityTimeout in karma
config. It seems it took too long to compile a bundle so the browser was
killed before the bundle was ready.

// Timeout for capturing a browser (in ms).
captureTimeout: 60 * 1e3,

// to avoid DISCONNECTED messages
browserDisconnectTimeout : 10000, // default 2000
browserDisconnectTolerance : 1, // default 0
browserNoActivityTimeout : 60 * 1e3, //default 10000