Clarifies the subject of this post

* Previously mentioned only modules in the title but also explains
* the Resolver
intro 1st draft
restructure 1st paragraph
Clarify function and replacing default resolver
finish explaining old resolver, start explaining new one
update intro, explanation of resolvers, and clean up examples
update to intro an examples
fix format
without word wrap
with soft wrap
Make a note about Pods
Improve structure
Use previous existing sentence to denote resolve
Improve explanation on es6
Merge pull request #2430 from ulisesrmzroche/explain-how-the-resolver-and-module-systems-work

Clarify how the Resolver and Module Systems work