eigen: modernize

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
eigen 3.2.3

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
eigen: install FindEigen3.cmake

Fixes #35225.
Closes #35243.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
eigen: update 3.2.3 bottle.
ruby 2.2.0

Closes #35250.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
ruby: update 2.2.0 bottle.
ruby-build 20141225

Closes #35251.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
nvm 0.21.0

nvm 0.21.0

Closes #35252.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
postgresql: drop questionable gem installation caveats
hub 1.12.4

Closes #35255.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
requirements: recommend casks where available.

Also, tweak the XQuartz requirement to not show 0.0.0 versions being required.

Closes #35254.

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