added 'rake pry' task
added Proc#| and Funkify#pass

Proc#| allows composition from left to right as opposed to the normal
right to left composition of Proc#*.

'pass' injects a value into the start of a | stream, i.e

pass(5) | (add(2) | mult(3)) #=> 21
added multi-arg support to 'pass'

e.g: pass(5, 6) | (mult | add(6)) #=> 36
added tests for | reverse-composition operator

e.g: (add(5) | mult(2)).(10) #=> 30
compare to normal composition: (add(5) * mult(2)).(10) #=> 25