Get rid of scalaj-collections

[wsuchy]

There is no Scala 2.12 version of that library.

[codecov]

Codecov Report

Merging #333 into master will decrease coverage by 0.04%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #333      +/-   ##
==========================================
- Coverage   86.58%   86.54%   -0.05%     
==========================================
  Files         335      335              
  Lines       10748    10751       +3     
  Branches      359      354       -5     
==========================================
- Hits         9306     9304       -2     
- Misses       1442     1447       +5

Impacted Files	Coverage Δ
...ala/com/salesforce/op/features/types/package.scala	51.06% <0%> (-1.12%)	⬇️
...es/src/main/scala/com/salesforce/op/OpParams.scala	85.71% <0%> (-4.09%)	⬇️

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[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @wsuchy to sign the Salesforce.com Contributor License Agreement.