Add Expression Inliner for includes

[araddon]

closes #181 allow nested expressions that are referenced by the INCLUDE statement to be inlined for easier reading.

[codecov-io]

Codecov Report

Merging #182 into master will increase coverage by 0.24%.
The diff coverage is 64.7%.

@@            Coverage Diff             @@
##           master     #182      +/-   ##
==========================================
+ Coverage   39.89%   40.14%   +0.24%     
==========================================
  Files          83       84       +1     
  Lines       24956    25007      +51     
==========================================
+ Hits         9956    10038      +82     
+ Misses      13268    13233      -35     
- Partials     1732     1736       +4

Impacted Files	Coverage Δ
rel/parse_filterql.go	57.69% <ø> (ø)	⬆️
expr/node.go	45.56% <33.33%> (+1.5%)	⬆️
expr/include.go	74.35% <74.35%> (ø)
expr/stringutil.go	79.54% <0%> (+3.03%)	⬆️
expr/parse.go	60.6% <0%> (+3.18%)	⬆️
expr/funcs.go	52.63% <0%> (+21.05%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 253bf47...e8f69bf. Read the comment docs.