Implements event

[RomainFrancony]

Events

As in #27, I needed more controls on Impetus lifecycle so I added events :

• onStart : called when starting to drag the element
• onStartDecelerating : called when the deceleration begun
• onEndDecelerating : called when the deceleration has ended

Caution update is now onUpdate in order to be more consistent on naming

Build on Windows

I added a few dependencies in order to be able to build on Windows (for rm and cp command)

[panec]

👍