Cleanse README, add ToDo ideas
Refactoring erlc calls using local vars. Also, cleansing.

* Fix typo in README
* Simplify $(wildcard …) using shell globbing
* Clarify some comments
* Recursive calls made to $(MAKE) instead of just make
* Use local variables (rule: lvar = value) in erlc commands
    * expanded on call and not on declaration
    * more readable code
* Replace -pa with -pz everywhere
* Expand -pz deps/*/ebin/ in multiple -pz's (fixes a bug)