Expose the expanded argument list from ParseResult

[mashlol]

Written to solve #1074 , this exposes the expanded argument list that picocli keeps internally. I had to reverse the list since it was stored as a stack, which I believe means we're copying the full argument list twice into memory. Ideally we'd use some sort of reversed view and not duplicate it, but since we don't have guava or anything like that it's slightly ugly imo. Happy to update with that though.

[codecov-commenter]

Codecov Report

Merging #1075 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master    #1075   +/-   ##
=========================================
  Coverage     94.45%   94.46%           
  Complexity      448      448           
=========================================
  Files             2        2           
  Lines          6564     6571    +7     
  Branches       1765     1765           
=========================================
+ Hits           6200     6207    +7     
  Misses           93       93           
  Partials        271      271           

Impacted Files	Coverage Δ	Complexity Δ
src/main/java/picocli/CommandLine.java	94.31% <100.00%> (+<0.01%)	309.00 <0.00> (ø)

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[remkop]

Merged into master.
Thank you for the contribution!