Use shared_ptr to manage io_data_t*.
Convert all io_data_t copying to shared_ptr copying.

Copy constructor of io_data_t is removed.
Use const shared_ptr<io_data_t>& instead of copying where appropriate.
make 'alias' check for recursive calls and insert 'command'; update docs, fix #486
re-enable tests that were accidentally disabled in 0b1e3718
Remove origin/HEAD lines from __fish_git_branches.

Related discussion:
http://stackoverflow.com/questions/354312/why-is-origin-head-shown-when-running-git-branch-r
fix bug in export status of universal variable assignment
really fix bug in export status of universal vars; add tests for that bug
Make share/man/man1 manpages get built again
Addresses https://github.com/fish-shell/fish-shell/issues/491
Make the Makefile mv man pages instead of cp them from help_doc, because help_doc is about to be deleted
Change build_documentation to take its paths as arguments, and the Makefile.in to pass them
Teach Xcode how to pass arguments to build_documentation.sh
Teach the Xcode project how to install the man pages
Merge branch 'oo-io' of git://github.com/xiaq/fish-shell into xiaq-oo-io
Replace some shared_ptrs with const shared_ptr &. Don't use shared_ptr in postfork.cpp. Eliminate copy constructor in io_data_t. Simplify some other uses of shared_ptr<io_data_t>
Remove io_duplicate, which is no longer used
Revert shared_ptr<io_data_t> changes until kinks are ironed out
https://github.com/fish-shell/fish-shell/pull/487

Revert "Merge branch 'oo-io' of git://github.com/xiaq/fish-shell into xiaq-oo-io"

This reverts commit f3c8f535a48d5fdd518bd60879ade948bc8be7e6, reversing
changes made to b02f6cf3bc4343cf3e068dee3cb46de7139a5a27.

Also reverts ac023f7588e562a03fdea7fd2feda487f18827c7 and a79d3c680c9548566309121630dadc94e48934c4
Hack around xdm's dumb assumption that the login shell is POSIX compliant so we no longer kill OpenSUSE
https://github.com/fish-shell/fish-shell/issues/367
Also fix some formatting
Reset the color before we clear to eol
Fixes https://github.com/fish-shell/fish-shell/issues/493
Implement builtin [ via builtin test