CucumberOpts.compiler doesn't handle compiler options correctly

[kamolins3]

In readme there is an example of passing compiler options to such as:
[ ['js:babel-register', { ignore: [] }] ]

Error thrown is compiler.split is not a function

Looking into it a bit in wdio-cucumber-framework/build/adapter.js:222

This function here:

 value: function registerCompilers() {
            this.cucumberOpts.compiler.forEach(function (compiler) {
                var parts = compiler.split(':');
                require(parts[1]);
            });
        }

Compiler array passed to it looks like this:

[ 'js:babel-register', { ignore: [] } ]

wdio-cucumber-framework 2.2.8