Live Updates from Xcode Server

[czechboy0]

Xcode Server has an endpoint for getting updates from it in real time. This PR uses it and exposes it to users in a nice way. This is useful if you want to show e.g. progress bar/better idea of what XCS is running right now, like Xcode does when you select a running Integration.

for more info see buildasaurs/Buildasaur#7

[buildasaur]

Result of Integration 1

Duration: 1 minute and 12 seconds
Result: All 73 tests passed, but please fix 2 warnings.
Test Coverage: 56%.

[buildasaur]

Result of Integration 3

Duration: 45 seconds
Result: All 73 tests passed, but please fix 1 warning.
Test Coverage: 56%.

[buildasaur]

Result of Integration 4

Duration: 53 seconds
Result: Perfect build! All 73 tests passed. 👍
Test Coverage: 56%.

[buildasaur]

Result of Integration 5

Duration: 1 minute and 0 second
Result: Perfect build! All 73 tests passed. 👍
Test Coverage: 56%.