Add munit for unit testing.

Main method extracted to separate file to make it easier to test the _rest_ of the code.
munit is added as a submodule by running `cd src; git submodule add https://github.com/nemequ/munit.git` .

Unit testing has so far only been tested on ubuntu.

src/test/test_handler.c

@@ -0,0 +1,40 @@
+#include "test_handler.h"
+
+static void run_single_get_number_test(const char* input_param, const char *name_result, int number_result);
+
+UNIT_TEST(test_get_number)
+{
+  run_single_get_number_test("1.feather", "feather", 1);
+  run_single_get_number_test("2.feather", "feather", 2);
+  run_single_get_number_test("1.feat", "feat", 1);
+  run_single_get_number_test("feather", "feather", 1);
+  run_single_get_number_test("10.feather", "feather", 10);
+
+  return MUNIT_OK;
+}
+
+static void run_single_get_number_test(const char* input_param, const char *name_result, int number_result)
+{
+  char *to_free;
+  char *input = to_free = strdup(input_param);
+
+  int number = get_number(&input);
+  munit_assert_int32(number, ==, number_result);
+  munit_assert_string_equal(input, name_result);
+  
+  free(to_free);
+}
+
+/* Creating a test suite is pretty simple.  First, you'll need an
+ * array of tests: */
+MunitTest handler_c_tests[] = {
+  {
+    (char*) "/get_number",
+    test_get_number,
+    NULL, // setup callback
+    NULL, // cleanup callback
+    MUNIT_TEST_OPTION_NONE,
+    NULL
+  },
+  { NULL, NULL, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL }
+};