Use a case-sensitive version of SafeConfigParser everywhere
This change has the potential to break existing setups, but the current
behaviour (the keys in configuration files are always lower-cased) can
bite us in a few places:
- no way to use a Command in [defaults]
- hgext.Extension doesn't work in [extensions]
- you can't use an Upper/case/PATH in the [paths] section of hgweb.config
- you can't (easily) protect paths with upper-case letters with the
acl extension
- you can't specify a /Path/TO/a/rEPO in the [reposubs] section for
the notify extension
*** 'a\nc\n\n\n\n' 'a\nb\n\n\n'
*** 'a\nb\nc\n' 'a\nc\n'
*** '' ''
*** 'a\nb\nc' 'a\nb\nc'
*** 'a\nb\nc\nd\n' 'a\nd\n'
*** 'a\nb\nc\nd\n' 'a\nc\ne\n'
*** 'a\nb\nc\n' 'a\nc\n'
*** 'a\n' 'c\na\nb\n'
*** 'a\n' ''
*** 'a\n' 'b\nc\n'
*** 'a\n' 'c\na\n'
*** '' 'adjfkjdjksdhfksj'
*** '' 'ab'
*** '' 'abc'
*** 'a' 'a'
*** 'ab' 'ab'
*** 'abc' 'abc'
*** 'a\n' 'a\n'
*** 'a\nb' 'a\nb'
done