Use strongly-typed enum flags.

[brianhou]

#339 might not be ideal because the "options" can be arbitrary ints, rather than combinations of the options that we actually enumerate. If that's a problem, maybe something like this would be better?

This PR follows the blog post above. I think the biggest annoyance with this implementation is that there's no contextual conversion to bool, so you can't write something like if (mOptions & Options::POSITIONS). My intermediate workaround is to require Options::NONE = 0 and compare directly to that.

I'm not entirely convinced whether this complication is worth it. @jslee02, what do you think?

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[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@c08d6a4). Click here to learn what that means.
The diff coverage is 72.72%.

@@            Coverage Diff            @@
##             master     #340   +/-   ##
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  Coverage          ?   77.62%           
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  Files             ?      261           
  Lines             ?     6592           
  Branches          ?        0           
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  Hits              ?     5117           
  Misses            ?     1475           
  Partials          ?        0

Impacted Files	Coverage Δ
src/planner/WorldStateSaver.cpp	0% <0%> (ø)
src/statespace/dart/MetaSkeletonStateSaver.cpp	76% <100%> (ø)
include/aikido/common/EnumFlags.hpp	100% <100%> (ø)

[jslee02]

Sorry for the late response. This looks great to me!

[jslee02]

Nit: template <> (a space between template and the angle brackets)

[jslee02]

Nit: Maybe we want to make this as non-doxygen style comment because this comment is not specifically tied to a code but just a note?

[psigen]

Just curious @brianhou @jslee02, can you implement something like the following to make that explicit boolean cast work?

(See Update section)
https://stackoverflow.com/a/9883421

[egordon]

Outdated, to consider for later