Refactor conversion of None to empty introduced in #49 and #40

[jashgala]

Supersedes #93

(Had to create a new branch since I messed up the original branch!)

Handled refactoring discussed in Issue #52.

Moved check for None to TextUtils and updated the github.py functions to use that instead of directly checking in the function itself.

[codecov-io]

Current coverage is 95.21% (diff: 100%)

Merging #100 into master will increase coverage by <.01%

@@             master       #100   diff @@
==========================================
  Files            34         34          
  Lines          2105       2109     +4   
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
+ Hits           2004       2008     +4   
  Misses          101        101          
  Partials          0          0          

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[donnemartin]

@jashgala thank you!