Adding support for outer/cross apply

[blocka]

This PR adds apply, outer_apply and cross_apply to mssql flavor select.

[codecov]

Codecov Report

Merging #346 into master will increase coverage by 0.14%.
The diff coverage is 90.76%.

@@            Coverage Diff             @@
##           master     #346      +/-   ##
==========================================
+ Coverage   81.31%   81.46%   +0.14%     
==========================================
  Files           2        2              
  Lines        2863     2913      +50     
  Branches      635      644       +9     
==========================================
+ Hits         2328     2373      +45     
- Misses        535      540       +5

Impacted Files	Coverage Δ
dist/squel.js	72.8% <90.76%> (+0.52%)	⬆️

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[mkndn]

Can you please tell me when its planned to be made available. I really need this...

[blocka]

Any news on this? I understand this is open source, and you don't have all the time in the world for this, but that's what PR's are for...