Initial QSfera import

Server/vendor/github.com/gookit/goutil/byteutil/check.go

@@ -0,0 +1,9 @@
+package byteutil
+
+// IsNumChar returns true if the given character is a numeric, otherwise false.
+func IsNumChar(c byte) bool { return c >= '0' && c <= '9' }
+
+// IsAlphaChar returns true if the given character is a alphabet, otherwise false.
+func IsAlphaChar(c byte) bool {
+	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
+}