Move invocation of initialize above setting of attributes and validation

[TylerBrock]

If initialize is used to initialize objects (provide defaults, etc) it should happen before the provided attributes are set on the object and validated, not after.

This attempts to resolve part of the second blocker in #73.

[codecov-io]

Current coverage is 85.22%

Merging #81 into master will increase coverage by +0.03% as of f2a68f9

@@            master     #81   diff @@
======================================
  Files           37      37       
  Stmts         2796    2796       
  Branches         0       0       
  Methods          0       0       
======================================
+ Hit           2382    2383     +1
  Partial          0       0       
+ Missed         414     413     -1

Review entire Coverage Diff as of f2a68f9

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