不再自动调用 jieba 分词模块，改为自动调用内置的最大匹配分词模块来分词

[mozillazg]

closed #100

[coveralls]

Coverage decreased (-0.01%) to 99.235% when pulling 1e65e3f on no-jieba into 76f92c7 on master.

[codecov]

Codecov Report

Merging #102 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #102      +/-   ##
==========================================
- Coverage   99.24%   99.23%   -0.02%     
==========================================
  Files          20       20              
  Lines         530      523       -7     
==========================================
- Hits          526      519       -7     
  Misses          4        4

Impacted Files	Coverage Δ
pypinyin/contrib/mmseg.py	100% <100%> (ø)	⬆️
pypinyin/core.py	100% <100%> (ø)	⬆️

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[mozillazg]

@bors-homu r+

[bors-homu]

📌 Commit 1e65e3f has been approved by mozillazg

[bors-homu]

⌛ Testing commit 1e65e3f with merge 64d9ff6...

[bors-homu]

☀️ Test successful - status-travis
Approved by: mozillazg
Pushing 64d9ff6 to master...