Adding 'list_bullets' feature

[naokazuterada]

Hi @jonasbn , I added a new feature 'list_bullets' due to #41.

Could you review README?

Thank you.

[coveralls]

Coverage increased (+0.06%) to 92.115% when pulling c3b8bcf on list-bullets into 3443ab5 on master.

[codecov]

Codecov Report

Merging #102 into master will increase coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #102      +/-   ##
==========================================
+ Coverage   92.05%   92.11%   +0.05%     
==========================================
  Files           1        1              
  Lines         277      279       +2     
==========================================
+ Hits          255      257       +2     
  Misses         22       22

Impacted Files	Coverage Δ
MarkdownTOC.py	92.11% <100%> (+0.05%)	⬆️

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[jonasbn]

Looks good, nifty feature

[naokazuterada]

@jonasbn Thank you! 👍