[emacs] Moved packages requiring emacs-24.

Several packages that actually require emacs-24 were in the wrong
section.
[packages] Added Perforce Jam to packages to install.
[python] Added Python packages for Python development.

autopep8 - formats Python files according to PEP-8
docformatter - formats Python docstrings according to PEP-257
[python] Organized Python requirements.

This clarifies the reasons for installing various Python packages.
[ruby] Removed unnecessary Ruby gems.
[ruby] Organized Ruby gems into sections.
[packages] Clarified llvm installation.

This is key-only in Homebrew and does not include the compiler so just
install it from the bottle.
[python] Added some more modules.
[packages] Added shellcheck from Homebrew.
[packages] Do not install special python or ruby.

This does not install Python or Ruby from Homebrew to force us to use
the system versions.
[python] Added PEP-8 naming checking package.
[bash] Minor comment cleanups.
[install] Fix detection and setting of git user.

This was previously using the local Git configuration of this repository
instead of the user's Git configuration.
[install] Install Python packages in install script.

The install script now installs pip and the desired packages.
[install] Install Ruby packages in install script.

The install script now installs bundler and the desired packages.
[install] Install Node.js modules in install script.
[emacs] Conditionally require more packages.
[emacs] Cleaned up some comments.
[emacs] Fixed commenting and spacing.
[packages] Split out language package installs.

These can now be run independently of the rest of the install if
required.

This still needs some more work to simplify and give the user some
control over what gets done.