Fix spelling error.
Remove trailing whitespace.
More spelling fixes.
Add requirements regarding case-sensitivity.
Merge pull request #216 from Crell/psr-4-case-folding

Psr 4 case folding
Merge branch 'master' of github.com:php-fig/fig-standards

Conflicts (resolved):
	proposed/psr-4-autoloader/psr-4-autoloader.md