add MySQL INSERT IGNORE support & fix escape issue

[yibn2008]

changes:

• fix MySQL escape issue string escape is incorrect, especially when string contains \n or ', which may cause SQL injection #366
• support MySQL INSERT IGNORE INSERT IGNORE support for MySQL #354

[codecov]

Codecov Report

Merging #367 into master will decrease coverage by 0.07%.
The diff coverage is 95.87%.

@@            Coverage Diff             @@
##           master     #367      +/-   ##
==========================================
- Coverage   81.31%   81.24%   -0.08%     
==========================================
  Files           2        2              
  Lines        2863     2884      +21     
  Branches      635      640       +5     
==========================================
+ Hits         2328     2343      +15     
- Misses        535      541       +6

Impacted Files	Coverage Δ
dist/squel-basic.js	93.39% <100%> (+0.01%)	⬆️
dist/squel.js	72.23% <95.6%> (-0.05%)	⬇️

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