Resolve "export genomic context to svg or png"

Closes #21 (closed)

frontend/composables/useDownloadBlob.ts

+export function useDownloadBlob() {
+    function download(blob: MaybeRef<Blob>, filename: MaybeRef<string>) {
+        const toValueBlob = toValue(blob)
+        const toValueFilename = toValue(filename)
+        var a = document.createElement("a");
+        a.href = URL.createObjectURL(toValueBlob);
+        a.download = toValueFilename;
+        a.click();
+        URL.revokeObjectURL(a.href);
+    }
+
+    return { download }
+
+}
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