Ability to pass options in the macro content itself rather than as a macro parameter

The ChartJS library uses two main JavaScript objects: one for the data, one for the options. Currently, the ChartJS macro makes it possible to pass the options as a parameter. However, when dealing with complex options, the need to escape all the quotes makes the options not easy to read. Also, this way, it's not possible to pass functions (the JSON representation does not encompass functions). An improvement could consist in making it possible to pass both the data and the options in the macro content:

{{chartjs}}
[json data]
----
[json options]
{{/chartjs}}