Required according to RFC 3986:

> An implementation should accept uppercase letters as equivalent to
> lowercase in scheme names

Closes #330

This typo was present since the option was added in commit ed001e0c

`AllocatedPath::FromUTF8Throw()` will never return a nulled instance.

Don't use the bad `FatalError` library.

Let MainOrThrow() forward it to mpd_main().

Deinitialize the logging library after the last exception handler,
because that one could still need it.

Use `AtScopeExit()` to ensure it's always called, even if an exception
was thrown.

the code here tried to guard DSD features behind ENABLE_DSD. However, the sample rate setting should be shared between two scenarios. 

https://github.com/MusicPlayerDaemon/MPD/commit/40a1ebee295c569521ea17ffdedc641d1aedd9cb#diff-ce7ecec9ea9ca3df90d9c290cb3ef9d4R795


The code runs fine if the dac supports the sample rate, as Mac OS  will use the device rate if stream rate is 0. 
However, when DAC is uncapable of processing the sample rate, a wrong rate (device rate) will be used for the stream rate.

Add link to more recent libsidplayfp and correct URL pointing to libsidplay2.