Add support for optional job document fields

[kstribrnAmzn]

Description

FileType (for example) is optional in a job document. If the field exists, parse it. If not, skip it.

Testing

Executed updated unit tests per README instructions.

Issue

See #114

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[kstribrnAmzn]

Expecting memory stats to fail. I'll update this with the new memory footprint after the failure.

[kstribrnAmzn]

Coverage is failing because the C compiler version file created by CMake cannot be found. It's expected in the build directory but has since moved to <build-dir>/MakeFiles/3.28.3/CompilerIdC/. Not sure why this is the case. I'm assuming it's due to the latest CMake version

[kstribrnAmzn]

       --branch-coverage
              Collect and/or retain branch coverage data.

              This is equivalent to using the option "--rc lcov_branch_coverage=1"; the option was added to better match the genhml interface.

Per the man page this is the same as --rc lcov_branch_coverage=1 but using this instead creates failures. Will leave Gaurav's commit as is. His works.