Faster and 0-alloc random
Improve Meter

* Use timer instead of no ending task
* Use UtcNow instead of Now
Merge pull request #4 from razrin/master

Use SortedList instead of SortedDictionnary
Merge pull request #5 from razrin/topic/fastRand

Faster and 0-alloc random
Merge pull request #6 from razrin/topic/betterMeter

Improve Meter
Various fixes on DecayingSample

* Fix out of bound lookup when priority collides
* Fix time unit of the rescaling interval