coleslaw: Add modeline to zle configuration.

Also remove the hashbang.
coleslaw: Suffix ".template" to zsh script name.

Also use new Colemak project name, "Colemakerel".
coleslaw: Rename to colemakerel and organize templates.

Begin process of shifting to a makefile-based install system that uses
per-module subdirectory structure to dictate where each file will be
installed.
Reorganize templates.
Replace shell scripts with makefiles.
Rewrite to use templates and makefiles.

The previous setup used shell scripts. The output files and symlinks
were generated either directly by the scripts or by substituting values
into template files. The locations for the output were encoded directly
into the scripts, so customizing install locations required editing the
scripts directly. Overwriting existing symlinks required passing flags
to the setup programs. Overall, it was pretty clunky.

I've rewritten the installers as GNU makefiles and reorganized the
subdirectories. Each subdirectory is now considered a "module"
containing the dotfiles relevant to a particular piece of software. By
default, every file contained in a module is treated as a template to be
filled in and installed. (The standard substitutions are defined in the
top-level makefile.) All output files are generated; none are symlinked.
The location of a template within the module determines where that
template will be installed. For instance:

- git/.gitconfig ->
    $(prefix)/.gitconfig
- macports/.zsh/startup/macports.zshenv ->
    $(prefix)/.zsh/startup/macports.zshenv
- tmux/.zsh/startup/tmux.zlogin ->
    $(prefix)/.zsh/startup/tmux.zlogin

Thus, each module can be viewed as a "slice" of the target directory
structure; the final installation is produced by layering the slices.

This default behavior can be overriden on a per-module basis through the
"module.mk" sub-makefiles, which are included by the top-level makefile.
Sub-makefiles may include custom substitutions, targets, etc.