Sorry sorry sorry!

Accidentally pushed to the wrong remote... could have sworn
my own was set as the default.

This reverts commit b67e685620d5ee21816459901f722f0fd639b496.
Replace sceaga/homebrew with mistydemeo/tigerbrew

@sceaga has discontinued his fork of homebrew.
Only use curl -k on Leopard
Update clang regex for build 425

Regex borrowed from MacOS.clang_build_version.

Fixes #18755.
Don't try to install from git if git is too old

This came up in tigerbrew, where the install failed for a user with
git 1.6.x: https://github.com/mistydemeo/tigerbrew/issues/9

TODO Given that this left the user with a chowned /usr/local but no
functional homebrew install, there should still be better error
handling here.

Fixes mistydemeo/tigerbrew#9.
Fixes #20945.
Closes #18666.
Curl flags: <= 10.5

So I can be lazy and not change this downstream
Merge remote-tracking branch 'mxcl/go' into go

Conflicts:
	install