- library: check symbol->primary for escape sequences also

- GUI: error message GS1_MODE -> GS1 mode
- GUI: sequence window: fix initial clear button status
- GUI: make acceptable for macOS; add iconset for macOS, install
- manual: update macOS Homebrew install info; add README.macos
- GUI: export window: add no. of sequences to results label

frontend/test.sh

@@ -1,3 +1,5 @@
+#! /bin/bash
+# Create zint test output
 mkdir test_sh_out
 cd test_sh_out
 echo testing Code 11