Install executables in examples tree and print more meaningful error …

[PhilipFackler]

Description

• Add direct output and exit without an exception
• Make help message more helpful
• Install target binaries in examples tree in the same place as the JSON files

Closes #252

This is intended to more appropriately implement the changes requested in #235.

Proposed changes

• Help message explains you either provide the input file on the command line or run from the example directory
• The bin install destination should be reserved for actual project executables. It makes more sense for example executables to live under share, and that's where I already had the JSON files being installed. This also follows the convention of the build tree.

Checklist

• All tests pass.
• Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
• The new code follows GridKit™ style guidelines.
• There are unit tests for the new code.
• The new code is documented.
• The feature branch is rebased with respect to the target branch.
• I have updated CHANGELOG.md to reflect the changes in this PR. If this is a minor PR that is part of a larger fix already included in the file, state so.
  • NOTE: this is a follow-up fix for Refactored TinyTwoBus examples to use separate JSON files #250 which has already been noted in the changelog.

[pelesh]

All tests need to pass.

@nkoukpaizan, is the failing test perhaps due to #234?

[nkoukpaizan]

All tests need to pass.

@nkoukpaizan, is the failing test perhaps due to #234?

Yes, it is due to #234.

[pelesh]

lgtm