Modernize codebase

.eslintrc.js

.jshintrc

package-lock.json

package.json

sitegin/config.js

sitegin/gitInfo.js

sitegin/image.js

sitegin/imageResizer.js

sitegin/jobs.js

sitegin/markdown.js

sitegin/nunjucks.js

sitegin/parseHugo.js

sitegin/parseRedirects.js

sitegin/pipeline.js

sitegin/print.js

sitegin/readFiles.js

sitegin/resetJobs.js

sitegin/sitegin.js

sitegin/sitemap.js

sitegin/tags.js