CHANGE LOG:
FIXED an issue with the placeable checks still allowing placement of blocks with stacked items ( Issue 16).
ADDED support for PlaceholderAPI in the lore of your custom items. The placeholders are parsed upon completing a valid crafting matrix in the crafting table. I have implemented it into the recipe booklet as well. This is just the beginning 'beta' version as I plan on expanding this to something more.
ADDED custom placeholders via PlaceholderAPI to be used in holograms and other locations. More will be added soon. If you have any suggestions as far as placeholders go, please let me know.

Other placeholders are found here.
Current placeholders:
(recipeName is replaced with the name of your recipe (likely the file name))
(slot is replaced with the slot (1-9) in the crafting table)

Returns the material of the ingredient in the specified slot:
- %customrecipes_ recipeName _ingredient_ slot %
Returns the name of the ingredient in the specified slot:
- %customrecipes_ recipeName _ingredient_name_ slot %
Returns the required amount of the ingredient in the specified slot:
- %customrecipes_ recipeName _ingredient_amount_ slot %
Returns the identifier of the ingredient in the specified slot:
- %customrecipes_ recipeName _ingredient_identifier_ slot %