FDroidPopen must have a locale to support UTF-8 filenames

`fdroid update` should be able to handle any valid filename (hopefully
aapt doesn't barf on them).  To handle that, the environment where the
shell commands are run in needs to have a UTF-8 locale set. If LANG is
not set, things default to ASCII and UTF-8 filenames fail.

This also renames test APK with lots of Unicode chars as a test case.

closes #167

tests/run-tests

@@ -138,6 +138,20 @@ $fdroid readmeta
 $fdroid update
 
 
+#------------------------------------------------------------------------------#
+echo_header "copy tests/repo, generate a keystore, and update"
+
+REPOROOT=`create_test_dir`
+cd $REPOROOT
+$fdroid init
+cp -a $WORKSPACE/tests/metadata $WORKSPACE/tests/repo $REPOROOT/
+echo "accepted_formats = ['json', 'txt', 'xml', 'yml']" >> config.py
+$fdroid update --verbose
+test -e repo/index.xml
+test -e repo/index.jar
+grep -F '<application id=' repo/index.xml > /dev/null
+
+
 #------------------------------------------------------------------------------#
 echo_header "test metadata checks"