No Xcode 8 CLT for El Capitan

[Lawrence Velázquez]

Jack Howarth has noted on IRC that that Apple will not be releasing
a Command Line Tools package for Xcode 8 on El Capitan [*].

	There is no Command Line Tools (OS X 10.11) for Xcode
	8 package. Xcode 8 contains SDKs that are incompatible
	with earlier toolchains. Developers who want to make use
	of the Xcode 8 SDKs from the command line must choose
	the SDK with xcode-select. Developers on OS X El Capitan
	who have installed versions of the Command Line Tools
	(OS X 10.11) for Xcode 8 Beta should install Command
	Line Tools (OS X 10.11) for Xcode 7.3.1. (28234439)

Do we need to adjust our installation instructions to account for this?
The consequences of mixing the Xcode 7 CLT with Xcode 8 are not clear to
me; maybe it's not a problem at all.

[*]: http://adcdownload.apple.com/Developer_Tools/Xcode_8.1_beta/Release_Notes_for_Xcode_8.1_beta.pdf

vq