doctor: add caveats to avoid scaring people.

Sporadically people ask to whitelist doctor warnings or file issues when
there's nothing actually wrong. Help reassure such people with a
friendly message.

Closes #30230.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
cuetools 1.4.0

Since berlios.de is no longer around, this formula would not build so:
- updated homepage to github repo
- updated release from 1.3.1 to 1.4.0
- added patch required for compilation (see
  https://github.com/svend/cuetools/pull/18)
- removed non-applicable configure options
cuetools: add 1.4.0 bottle.

Closes #30291.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
xcode: add new package ID for Mavericks.

Closes #30296.