Fixed all PyICU test failure

[philiptzou]

As the title described. After installing PyICU a lot of test cases are failed. This patch fixed all the test cases and added 3 environments to Travis CI for testing circumstances of different Python versions when PyICU is installed.

But we'll skip PyPy with PyICU since PyICU causes segment fault.

[codecov-io]

Current coverage is 77.09%

Merging #142 into master will increase coverage by +3.50% as of 4b3f849

@@            master    #142   diff @@
======================================
  Files           14      14       
  Stmts         1545    1554     +9
  Branches       292     294     +2
  Methods          0       0       
======================================
+ Hit           1137    1198    +61
- Partial         92      93     +1
+ Missed         316     263    -53

Review entire Coverage Diff as of 4b3f849

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[bear]

nicely done!