First version with everything in... kind of!

All the code I had in mind is in, it considers:
 - "specific" substitutions
 - "same-type" substitutions
 - quantity adjustments

Some of the code is really the "quick'n'dirty" way to do things, but it
works the same way and would need to be optimised only for scalability
reasons.
Merge branch 'master' of https://github.com/snooze92/ke2013-recipe-adjustor.git