WIP: Supporting functions for array symbolics

[shashi]

builds on #215

[MasonProtter]

Just some preliminary thoughts

[shashi]

JuliaParallel/DistributedArrays.jl#4 is a good list of operations to wrap.

[codecov-io]

Codecov Report

Merging #123 (c5527fe) into master (e84bff9) will decrease coverage by 1.80%.
The diff coverage is 45.07%.

@@            Coverage Diff             @@
##           master     #123      +/-   ##
==========================================
- Coverage   86.10%   84.30%   -1.81%     
==========================================
  Files          12       13       +1     
  Lines         993     1153     +160     
==========================================
+ Hits          855      972     +117     
- Misses        138      181      +43     

Impacted Files	Coverage Δ
src/SymbolicUtils.jl	100.00% <ø> (ø)
src/arrays.jl	36.06% <36.06%> (ø)
src/types.jl	91.01% <100.00%> (+1.41%)	⬆️

---

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 e84bff9...c5527fe. Read the comment docs.

[codecov-commenter]

Codecov Report

Merging #123 (e982660) into master (cde48fa) will decrease coverage by 1.36%.
The diff coverage is 43.58%.

@@            Coverage Diff             @@
##           master     #123      +/-   ##
==========================================
- Coverage   85.31%   83.94%   -1.37%     
==========================================
  Files          12       12              
  Lines        1171     1202      +31     
==========================================
+ Hits          999     1009      +10     
- Misses        172      193      +21     

Impacted Files	Coverage Δ
src/methods.jl	79.06% <0.00%> (-5.94%)	⬇️
src/types.jl	84.77% <34.61%> (-3.09%)	⬇️
src/rule.jl	85.84% <50.00%> (-0.65%)	⬇️
src/abstractalgebra.jl	100.00% <100.00%> (+1.35%)	⬆️
src/api.jl	91.42% <100.00%> (ø)
src/ordering.jl	92.64% <100.00%> (+0.10%)	⬆️
src/code.jl	81.00% <0.00%> (-0.71%)	⬇️

---

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 cde48fa...e982660. Read the comment docs.

[shashi]

cc @YingboMa check out all the smilarterm changes lol, we should make that the default maybe?? But you were the one who switched it back to using promote_symtype.