Refactoring of pdt_locales

[philiptzou]

This is suggest refactoring version for issue #124 which intend to remove the redundant pdtLocale classes and init methods.

[philiptzou]

I struggled between the auto-discovering trick and this for a while. But when I realized that as import this said that "explicit is better than implicit", I thought we should just keep it like this -- simple and stupid -- even it's a bit redundant.

[bear]

+1 to keeping the locales list very simple and explicit

+1 to this PR

[codecov-io]

Current coverage is 73.29%

Merging #130 into master will increase coverage by +4.13% as of 2771d36

@@            master    #130   diff @@
======================================
  Files           13      14     +1
  Stmts         1683    1539   -144
  Branches       283     292     +9
  Methods          0       0       
======================================
- Hit           1164    1128    -36
- Partial         92      93     +1
+ Missed         427     318   -109

Review entire Coverage Diff as of 2771d36

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[philiptzou]

Just rebased.