Update installation scripts

[xloem]

I can now install using either script on my redhat system, even though redhat isn't supported yet.

• added check_cmd and install_pkg commands, to make it easy for users to manually install packages, and easy for maintainers to add new packaging systems
• normalised a few differences between the two scripts
• repaired the clone of epubjs which was broken due to a typo
• guard webpack and grunt runs with yarn so they don't need to be manually installed
• fix darwin download of wget to instead download curl, which is the tool actually used

[mitra42]

Thanks .. this install stuff is tough, getting it to work on so many platforms, but all your changes look good.

Could you add a comment to check_cmd - it took me a while to realize it was just to generate an error if the cmd isn't installed.

Also - you have removed the install of wget, which is used a couple of lines below (in both files) as part of the install of node, I think wget just needs to be installed with your check_cmd ... install_pkg sequence?

[mitra42]

Thanks - merged

[mitra42]

@xloem - I've been ignoring the dependabot merges as I haven't had time to test them individually. Every now and then I'd do a yarn upgrade which would catch them all, but that hasn't happened in a long time - except that I think you just did it.

If you think any of them should be merged, just drop a comment in there and I'll do it.

[xloem]

@mitra42 - you have a comment here that you merged this PR but it does not appear to be merged? i am probably missing something.

I haven't actually gotten the software to run yet to test non-crucial upgrades. Are you able to merge all the dependabot changes and test them briefly to make sure things still work?

I can likely help out by bundling them up into 1 single PR in a few days.

[mitra42]

Sorry - I might have missed the "Confirm Merge" step. It should be merged now.

Yes - I can merge the dependabots but I'm not in a position to run tests at the moment.

• Mitra