Replace usages of sprintf with snprintf

[nickbianco]

Brief summary of changes

As the title suggests, snprintf replaces all usages of sprintf, which can be dangerous because it can potentially output more characters than can fit in the allocation size of the buffer string. The change suppresses a gcc compiler warning (which was the main motivation for the PR).

Testing I've completed

Looking for feedback on...

CHANGELOG.md (choose one)

• no need to update because...not user facing.

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This change is 

[aymanhab]

One minor comment, otherwise LGTM

Reviewed 11 of 11 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @nickbianco)

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OpenSim/Common/IO.cpp line 286 at r1 (raw file):

    if(_GFormatForDoubleOutput) {
        snprintf(_DoubleFormat, 256, "%%g");
    } else if(_Scientific) {

Considering this number comes from a different file/header, it may make sense to define this as const integer BUFFER_LENGTH and refer to it by name to ensure they don't get out of sync.

[nickbianco]

Ready for review.

Reviewable status: 10 of 12 files reviewed, 1 unresolved discussion (waiting on @aymanhab)

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OpenSim/Common/IO.cpp line 286 at r1 (raw file):

Previously, aymanhab (Ayman Habib) wrote…

Considering this number comes from a different file/header, it may make sense to define this as const integer BUFFER_LENGTH and refer to it by name to ensure they don't get out of sync.

Good call, done. I added the constant and made the existing constant also constexpr.

[aymanhab]

Reviewed 2 of 2 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @nickbianco)