ENHANCEMENT Support global composer installation

[robbieaverill]

• Adds a new bin location for composer so we can use sspak still as the bin filename
• Rejigged readme to use # for titles, and added installation example with composer
• Tweaked a couple of constant values to ensure composer-compatible sspak works with B/C over original

Resolves #21

[helpfulrobot]

@robbieaverill, thanks for your PR! By analyzing the blame information on this pull request, I identified @sminnee, @wilr and @halkyon to be potential reviewers

[wilr]

👍

[dhensby]

This commit does a lot more than it says on the tin. Would you mind either splitting it into 3 commits or even 3 PRs?

1. Readme format update
2. Code style update
3. Adding composer global support (including new docs)

[robbieaverill]

Hey @dhensby - I've pushed an update separating the changes into three commits.

Is there a reason we can't have a unified bin file/location?

Yes - composer requires a single bin file declares for it to create symlinks. If I tell it to use bin/sspak then I don't have the ability to define the package root manually. There's possibly a way around it with some trickery in being able to detect that the package has been installed with composer, but this way allows you to still call sspak, but have the logic for it in a separate file.

You've just defined PACKAGE_ROOT - you should use it

Good point - updated.

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Tested with 3.x code - working correctly. The 4.x compatibility in #49 isn't quite there yet I don't think, may need a bit more tweaking: Path error: FRAMEWORK_PATH ... not within BASE_PATH ...

[dhensby]

OK - thanks.