Make all aliases optional (a la plugins)

This continues a pattern that was introduced in ffa45b0 and refined
further in later commits.  This enables all aliases by default, but can
be disabled by any user if they remove the appropriate
aliases/enabled/*.bash file.

aliases/available/jekyll.aliases.bash

@@ -0,0 +1,20 @@
+# Open the root of your site in your vim or builtin cd to it
+
+if [[ $EDITOR = "vim" ]]
+then 
+	alias newentry="builtin cd $JEKYLL_LOCAL_ROOT && $EDITOR ."
+else 
+	alias newentry="builtin cd $JEKYLL_LOCAL_ROOT"
+fi
+
+# Build and locally serve the site
+
+alias testsite="builtin cd $JEKYLL_LOCAL_ROOT && jekyll --server --auto"
+
+# Build but don't locally serve the site
+
+alias buildsite="builtin cd $JEKYLL_LOCAL_ROOT && rm -rf _site/ && jekyll"
+
+# Rsync the site to the remote server
+
+alias deploysite="builtin cd $JEKYLL_LOCAL_ROOT && rsync -rz _site/ $JEKYLL_REMOTE_ROOT"