add stop timeout option #291

Job	Run time
Apache2 tests on Linux	2m 21s
C++ tests on Linux	1m 20s
C++ tests on macOS	4m 15s
Nginx tests on Linux	2m 15s
Apache2 tests on macOS	2m 16s
Nginx tests on macOS	3m 7s
Homebrew packaging tests	6m 14s
Nginx dynamic module tests on Linux	1m 6s
Nginx dynamic module tests on macOS	1m 6s
Node.js tests on Linux	15s
Node.js tests on macOS	22s
Ruby tests on Linux	1m 4s
Ruby tests on macOS	1m 0s
Passenger Standalone tests on Linux	3m 36s
Passenger Standalone tests on macOS	4m 20s
Source packaging tests	25s
	35m 2s

Provide feedback