Update C++ SolutionArray interface to use 'int'

[ischoegl]

Changes proposed in this pull request

• Use int for all C++ SolutionArray interface methods
• Fixes MSVC warnings
• Avoids potential warnings from clib

Checklist

• The pull request includes a clear description of this code change
• Commit messages have short titles and reference relevant issues
• Build passes (scons build & scons test) and unit tests address code coverage
• Style & formatting of contributed code follows contributing guidelines
• The pull request is ready for review

[codecov]

Codecov Report

Merging #1520 (c6b24c1) into main (25fee18) will increase coverage by 0.00%.
The diff coverage is 75.43%.

❗ Current head c6b24c1 differs from pull request most recent head bde12f2. Consider uploading reports for the commit bde12f2 to get more accurate results

@@           Coverage Diff           @@
##             main    #1520   +/-   ##
=======================================
  Coverage   70.52%   70.52%           
=======================================
  Files         376      376           
  Lines       58913    58918    +5     
  Branches    21198    21198           
=======================================
+ Hits        41546    41551    +5     
  Misses      14308    14308           
  Partials     3059     3059           

Impacted Files	Coverage Δ
src/clib/ctfunc.cpp	32.71% <20.00%> (+0.63%)	⬆️
src/clib/Cabinet.h	54.41% <66.66%> (-0.67%)	⬇️
src/base/SolutionArray.cpp	78.85% <87.80%> (+0.07%)	⬆️
include/cantera/base/SolutionArray.h	94.44% <100.00%> (ø)
src/oneD/StFlow.cpp	82.18% <100.00%> (ø)

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[ischoegl]

@speth ... I cherry-picked the yaml-cpp commit from #1519, so this can all be taken care of at the same time.

[speth]

Thanks, @ischoegl. These updates look fine to me.