Resolve npm audit issues

[ubersloth]

Resolved npm audit issues and made the necessary code changes resulting from breaking changes in dependencies and from switching to eslint
Tests are passing

[TomasGottvald]

Hello Sapegin,
can you please merge this PR and release a new version with this fix please? In grunt-webfont there are 8 vulnerabilities now (1 low, 4 moderate, 3 high).
We are using your package in Shopsys Framework - https://github.com/shopsys/shopsys/ (fully functional ecommerce platform for businesses transitioning into tech-companies with their own software development team) and security is very important for us and our users so we want to have this solved as fast as possible.

Thank you for your cooperation.

[DavidOstrozlik]

Hello @sapegin ,

I'm just bumping this PR so it doesn't fade away, because this PR looks good and it's quite important for us.
I would be glad if you could take a look it this and solve this if possible.

Thanks a lot for the cooperation :)

[pesektomas]

Hello @ubersloth, thank you for this PR. When I tried your fork with this configuration:

{
	src: 'admin/*.svg',
	dest: 'assets/admin/fonts',
        destCss: 'styles/admin/',
        options: {
        	autoHint: false,
                font: 'svg',
                hashes: true,
                types: 'eot,woff,ttf,svg',
                engine: 'node',
                stylesheet: 'less',
                relativeFontPath: '../fonts',
                fontHeight: 512,
                descent: 0,
                destHtml: 'docs/generated',
                htmlDemo: true,
                htmlDemoTemplate: 'views/Grunt/htmlDocumentTemplate.html',
		htmlDemoFilename: 'webfont-admin-svg',
                templateOptions: {
			baseClass: 'svg',
                	classPrefix: 'svg-',
                	mixinPrefix: 'svg-'
		}
	}
}

I got error Fatal error: Expected a flag, got "00" at index "31". Do you know what this could cause? The problem is in node engine, but I don't know why.