Fix README image paths and dot description

Fixed paths to images for new repository dotfile delineation. Added
quick readme blurb explaining differece of normal and dotfile
directories.
Readme still explained old bare-repository directory structure. Rewrote
sentences to conform to new structure.

Removed underscore from bootstrap directory, since the repository does
not organize itself through underscore prefixes anymore.
Fixed package gathering git-hook to respect new bootstrap directory.

bootstrap/.config/sh/alias.d/dotlink.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env sh
+# relink all stowed files from anywhere
+# grepping is to remove meaningless stderr lines until this bug is fixed:
+# https://github.com/aspiers/stow/issues/65
+#
+# redirection is a neat way to filter stderr msgs by redirecting stderr
+# to stdout in a subshell, grepping in it, and redirecting back to stderr:
+# https://stackoverflow.com/a/15936384
+#
+# to customize this to your own needs, change the `push folder` to the
+# location of your dotfiles (stow) repository
+alias dotlink="pushd ~/.dotfiles;\
+  stow -R */ 2> >(grep -v 'Absolute/relative mismatch between Stow dir' 1>&2) ;\
+  popd"