`callApi` doesn't accept Long inputs, which are needed for timestamps.

Option inputs of type Long are ignored with line Line 246 of Uploader.java:

Lines 244-256 (https://github.com/cloudinary/cloudinary_android/blob/master/Cloudinary/src/com/cloudinary/Uploader.java#L244-L256)
```
		// Remove blank parameters
		for (Map.Entry<String, Object> param : params.entrySet()) {
			if (param.getValue() instanceof String || param.getValue() instanceof Integer) { 
				String value = Cloudinary.asString(param.getValue());
				if (!TextUtils.isEmpty(value)) {
					multipart.addFormField(param.getKey(), value);
				}
			} else if (param.getValue() instanceof Collection) {
				for (Object value : (Collection) param.getValue()) {
					multipart.addFormField(param.getKey()+"[]", Cloudinary.asString(value));					
				}
			}
		}
```




Long is useful for timestamps because they are very large numbers. The workaround is to pass timestamp in as a String.