Add testcase for nested markdown lists.

This will address github's issue #131.

t/20-text.t

@@ -25,7 +25,8 @@ push @tests, {
 };
 
 my @markdown_tests = qw(MarkDown PandocHeaderMultipleLines PandocOnlyAuthor
-    PandocTitleAndDate PandocMultipleAuthors PandocOnlyTitle PandocTitleAuthors);
+    PandocTitleAndDate PandocMultipleAuthors PandocOnlyTitle PandocTitleAuthors
+    MarkDownNestedLists);
 for my $markdown_test (@markdown_tests) {
     push @tests, {
         'run' => "perl ../../po4a-normalize -f text -o markdown ../t-20-text/$markdown_test.md > $markdown_test.err 2>&1".

t/t-20-text/MarkDownNestedLists.md

@@ -0,0 +1,8 @@
+This serves as testcase for nested lists.
+
+ * Item 1
+ * Item 2
+   * Nested item 1
+   * Nested item 2
+
+Normal paragraph.

t/t-20-text/MarkDownNestedLists.out

@@ -0,0 +1,8 @@
+This serves as testcase for nested lists.
+
+ * Item 1
+ * Item 2
+   * Nested item 1
+   * Nested item 2
+
+Normal paragraph.

t/t-20-text/MarkDownNestedLists.pot

@@ -0,0 +1,41 @@
+# SOME DESCRIPTIVE TITLE
+# Copyright (C) YEAR Free Software Foundation, Inc.
+# This file is distributed under the same license as the PACKAGE package.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: PACKAGE VERSION\n"
+"POT-Creation-Date: 2018-06-17 12:06+0200\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <LL@li.org>\n"
+"Language: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=CHARSET\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#. type: Plain text
+#: MarkDownNestedLists.md:2
+msgid "This serves as testcase for nested lists."
+msgstr ""
+
+#. type: Bullet: ' * '
+#: MarkDownNestedLists.md:7
+msgid "Item 1"
+msgstr ""
+
+#. type: Plain text
+#: MarkDownNestedLists.md:7
+#, no-wrap
+msgid ""
+" * Item 2\n"
+"   * Nested item 1\n"
+"   * Nested item 2\n"
+msgstr ""
+
+#. type: Plain text
+#: MarkDownNestedLists.md:8
+msgid "Normal paragraph."
+msgstr ""