A simple utility able to log measured time periods of various events. To create a new stopwatch, call:
sw := NewStopwatch(name string, log logging.Logger)
Stopwatch object can store a new entry with sw.LogTimeEntry(n interface{}, d time.Duration) where n is
a string representation of a measured entity (name of a function, struct or just simple string) and d is
time duration. If the name already exists, it will be indexed (for example name#1)
Use sw.Print() to print all measurements and clear stored entries.