Timeouts with standard high resolution clock

[Razican]

We should use std::chrono::high_resolution_clock for timeouts, since it gives us a better easier and more standard duration counter. More info: http://www.cplusplus.com/reference/chrono/high_resolution_clock/

[Razican]

Here we have an example of some code that will be on the next launch:

server/gsm/GSM.cc

Line 371 in e756fe4

chrono::high_resolution_clock::time_point start = chrono::high_resolution_clock::now();