Add newest generated code for Natural Language Classifier

[lpatino10]

This PR adds new newest generated code for Natural Language Classifier as of 2/8/18 for the purpose of the Java SDK 5.0.0 release.

[germanattanasio]

TODO

• Document breaking changes
• Verify that we can create a classifier with an in-memory CSV file.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (next@5ab49b9). Click here to learn what that means.
The diff coverage is 60.27%.

@@           Coverage Diff           @@
##             next     #863   +/-   ##
=======================================
  Coverage        ?   41.71%           
  Complexity      ?     1445           
=======================================
  Files           ?      473           
  Lines           ?    11593           
  Branches        ?      579           
=======================================
  Hits            ?     4836           
  Misses          ?     6465           
  Partials        ?      292

Impacted Files	Coverage Δ	Complexity Δ
..._language_classifier/v1/model/ClassifiedClass.java	33.33% <0%> (ø)	1 <0> (?)
...ge_classifier/v1/model/ListClassifiersOptions.java	0% <0%> (ø)	0 <0> (?)
...l_language_classifier/v1/model/ClassifierList.java	50% <100%> (ø)	1 <1> (?)
...tural_language_classifier/v1/model/Classifier.java	22.22% <16.66%> (ø)	1 <0> (?)
...l_language_classifier/v1/model/Classification.java	33.33% <25%> (ø)	2 <1> (?)
...e_classifier/v1/model/CreateClassifierOptions.java	57.5% <57.5%> (ø)	5 <5> (?)
...uage_classifier/v1/model/GetClassifierOptions.java	58.82% <58.82%> (ø)	2 <2> (?)
...e_classifier/v1/model/DeleteClassifierOptions.java	58.82% <58.82%> (ø)	2 <2> (?)
..._language_classifier/v1/model/ClassifyOptions.java	62.5% <62.5%> (ø)	3 <3> (?)
...guage_classifier/v1/NaturalLanguageClassifier.java	86.11% <96.42%> (ø)	7 <6> (?)

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[germanattanasio]

@lpatino10 Can you keep the existing methods at the bottom and adapt them to use the new methods? That way this won't be a breaking change.