Text copied from Terminal with formatting in Mavericks (10.9), Yosemite (10.10), and El Capitan (10.11)
You can disable copy/pasting the formatting from Terminal by changing the com.apple.Terminal preferences file.

Open Terminal on your Mac and enter the following command:
defaults write com.apple.Terminal CopyAttributesProfile com.apple.Terminal.no-attributes

This will strip all text attributes out of copy/pasting from Terminal