Fix broken css ref + file casing in appcompose

[vboctor]

Fixes #122

[msftclas]

Hi @vboctor, I'm your friendly neighborhood Microsoft Pull Request Bot (You can call me MSBOT). Thanks for your contribution!

This seems like a small (but important) contribution, so no Contribution License Agreement is required at this point. Real humans will now evaluate your PR.

TTYL, MSBOT;

[coveralls]

Coverage remained the same at 98.287% when pulling 0b50267 on vboctor:patch-2 into 8417f79 on OfficeDev:master.

[coveralls]

Coverage remained the same at 98.287% when pulling 0b50267 on vboctor:patch-2 into 8417f79 on OfficeDev:master.

[josteink]

I just hit this issue myself. This really should be fixed for anyone serving on a traditional Unix-like platform and webserver (Apache/Nginx/etc) where filename and URL casing matters. It's easy to fix, but why make it harder than necessary for people to get started?

Any reason this PR has not been merged yet?

[beth-panx]

Great spot!