Add zsh completion, remove compat hacks from bash

Ref #5

completion/_abra

@@ -0,0 +1,52 @@
+#compdef abra
+
+_abra () {
+	local context state line curcontext="$curcontext" ret=1
+	_arguments -n : \
+		{-h,--help}'[Help message]' \
+		'1:commands:(app server)' \
+		'*::arguments:->arguments' \
+		&& ret=0
+
+	case $state in
+		(arguments)
+			curcontext="${curcontext%:*:*}:abra-arguments-$words[1]:"
+			case $words[1] in
+				(app)
+					_arguments \
+						'1: :_abra_apps' \
+					&& ret=0
+				;;
+				(server)
+					_arguments \
+						'1:servers:_abra_servers' \
+					&& ret=0
+				;;
+			esac
+		;;
+	esac
+
+	return ret
+}
+
+_abra_servers() {
+	_path_files -/W $HOME/.abra/servers
+}
+
+_abra_apps()
+{
+	local newapps apps=($HOME/.abra/servers/*/*.env)
+	typeset -a apps
+	newapps=()
+	for app in $apps; do
+		newapps+=($(_abra_basename "${app}"))
+	done
+	_describe -t apps 'app' newapps
+}
+
+_abra_basename()
+{
+    printf -- "${1##*/}"
+}
+
+_abra "$@"