Add support for loading "templates" from InputStream

[strelok1]

WebXlsxExporter needs a constructor

WebXlsxExporter(InputStream stream) { 
... 
}

to support loading of templates from resources.

Right now the work around is:

def template =grailsApplication.parentContext.getResource("classpath:ReportTemplate.xlsx").inputStream
                    tempFile = File.createTempFile("ReportTemlate", ".xlsx")
                    tempFile << template
                    new WebXlsxExporter(tempFile.absolutePath).with { ... }

[nmaynes]

This issue held me up for more hours than I would like to admit. How can I contribute to adding a constructor?

[jmendiola222]

+1