Support RegEx for ignored files

[ronnyroeller]

We rename our *.js files for cache busting, e.g. the file my-file.js becomes my-file-<HASH>.js. Today, it's not possible to exclude files from gulp-inline without knowing their precise filename.

Hence, it would be great to allow regular expressions in the list of ignored files, e.g.:

inline({
  base: 'dist/',
  ignore: [
    'my-file-.*.js'
  ]
})

[ankon]

A bit of a discussion point: instead of adding regular expressions here (or globs?), one could instead also suggest to use https://github.com/robrich/gulp-if here.