Improve samples organization, add check script

samples/check.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+
+set -e
+
+for file in */*
+do
+    filetype="$(xdg-mime query filetype "${file}")"
+    if [ -z "${filetype}" ]
+    then
+        echo "${file}: no filetype found"
+        exit 1
+    fi
+    if [ "${file%.*}" != "${filetype}" ]
+    then
+        echo "${file} is not named according to filetype ${filetype}"
+        exit 1
+    fi
+
+    default="$(xdg-mime query default "${filetype}")"
+    if [ -z "${default}" ]
+    then
+        echo "${file}: ${filetype}: no default application found"
+        exit 1
+    fi
+
+    echo "${file}: ${filetype}: ${default}"
+done

samples/text/plain.txt

@@ -0,0 +1 @@
+This is a plain text file.