Fix #264: Add support of styling custom `titleFormatter`

[husa]

Fix #264 : Right now, there's no way to style console output with css when using custom titleFormatter.

This PR adds ability to return Array from titleFormatter that will be spread when passed to logger. Eg. support this:

createLogger({
  titleFormatter (action, time, took) {
    return [
      `%caction %c${action.type} %c@ ${time} %c(in ${took.toFixed(2)})`,
      'color: gray; font-weight: lighter;',
      'color: red;',
      'color: blue; font-weight: lighter;',
      'color: green; font-weight: lighter;'
    ];
  }
});

[codecov-io]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@539dab5). Click here to learn what that means. The diff coverage is 0%.

@@            Coverage Diff            @@
##             master     #265   +/-   ##
=========================================
  Coverage          ?   81.45%           
=========================================
  Files             ?        5           
  Lines             ?      151           
  Branches          ?        0           
=========================================
  Hits              ?      123           
  Misses            ?       28           
  Partials          ?        0

Impacted Files	Coverage Δ
src/core.js	72.36% <0%> (ø)

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[husa]

@evgenyrodionov for some reason, "codecov" can't find latest coverage report from master. Maybe it's because Travis build is failing on master.

[grushetsky]

@husa, the custom styling of log messages is going to be refactored in the next version of Redux Logger. You can read more about it in the issue #292.