Add ex2_04.coffee
Add ex2_05.coffee
Extend 2_05.coffee with EXPONENT & makeExptExtractor()
Add ex2_05.erl
DRY up ex2_05.erl w/extract/3 using recursive calls, iterative shape
Add Ex2_05.hs
Add ex2_05.rb
Rename EXPONENT -> BASE in ex2_05.coffee
Rename some inner functions in ex2_05.coffee