Add possibility to change date format

[phun-ky]

It should be possible to specify date format other than US

[alexcanessa]

@phun-ky could be related to #23. Definitely a good suggestion.

[alexcanessa]

We can add functions as template properties, so to evaluate wherever you want to customise.

P.S. The default date format is DD/MM/YYYY right now.

[urbanyeti]

Several years later but but it took me awhile to figure out how to do this with templates in a .grenrc.js file so I thought I would share what I used to convert DD/MM/YYYY to YYYY/MM/DD

"template": { release: function (placeholders) { var parts = placeholders.date.split("/"); var dt = new Date(parseInt(parts[2], 10), parseInt(parts[1], 10) - 1, parseInt(parts[0], 10)); return '## ' + placeholders.release + ' (' + dt.toISOString().substring(0, 10).replace(/-/g,"/") +")\n" + placeholders.body; } }