Add setting to ignore page number stored in file info. (Closes: #145)

Thanks for the patch to Urchlay.

config.c

@@ -97,6 +97,8 @@ config_load_default(zathura_t* zathura)
   girara_setting_add(gsession, "show-hidden",            &bool_value,  BOOLEAN, false, _("Show hidden files and directories"), NULL, NULL);
   bool_value = true;
   girara_setting_add(gsession, "show-directories",       &bool_value,  BOOLEAN, false, _("Show directories"), NULL, NULL);
+  bool_value = false;
+  girara_setting_add(gsession, "open-first-page",        &bool_value,  BOOLEAN, false, _("Always open on first page"), NULL, NULL);
 
   /* define default shortcuts */
   girara_shortcut_add(gsession, GDK_CONTROL_MASK, GDK_KEY_c,          NULL, sc_abort,                    0,          0,               NULL);

document.c

@@ -330,6 +330,13 @@ zathura_document_open(zathura_t* zathura, const char* path, const char* password
     document->pages[page_id] = page;
   }
 
+  /* jump to first page if setting enabled */
+  bool always_first_page = false;
+  girara_setting_get(zathura->ui.session, "open-first-page", &always_first_page);
+  if (always_first_page) {
+	  document->current_page_number = 0;
+  }
+
   /* apply open adjustment */
   char* adjust_open = "best-fit";
   document->adjust_mode = ADJUST_BESTFIT;