Truncate text by words

[bevacqua]

Consider using trunc-text instead of https://github.com/MaxArt2501/share-this/blob/master/src/sharers/twitter.js#L17, so that you don't get the last word butchered up when trying to share long bits of text.

[MaxArt2501]

Thanks for the suggestion, Nicolás. Although I don't consider the sharers provided by the package as a vital part of the library, I do intend to improve from being more than basic examples. Your utility seems like a good match for the task. I'll see if this fits in the next update.