Remove C version of `Coolio::Loop#initialize`
Remove C version of `Coolio::Loop#initialize`

Because we have Ruby version of Coolio::Loop#initialize.

This change can suppress following warnings:

lib/cool.io/loop.rb:41: warning: method redefined; discarding old initialize

tarcieri/cool.io,cosmo0920/cool.io,tarcieri/cool.io,tarcieri/cool.io,cosmo0920/cool.io