font unit, overflow updates and fixed examples

[samueljim]

• Added stopOverflow. If there is too much text then the text will still overflow outside of the div at the smallest font size. Setting stopOverflow to true will add a .overflow class to the selected div if the text is overflowing. It also adds CSS which hides the text that is overflowing in order to keep the design of the page.
• Added maxLines. Similar to stopOverflow but instead it adds the class if theres too many lines of text. This setting takes an input of false or a number of lines to apply the limit at. This needs to be improved but it's still useful to have now.
• Added fontUnit. Changes the unit used in the minFontSize and maxFontSize. This allows units such as cm, mm, in, pt, pc, em, vw, vh, % and rem to be used instead of px.
• Added fontChangeSize. This changes the amount of the font is changed by when trying to find the final font size. The default is 1 but changing this to a decimal is sometimes needed. When using rem or em font units 0.1 or 0.01 is a recommended change size.

Please let me know if you have any questions :)

[JacksonWolff]

Really interested on this PR @STRML, any plans for bring the fontUnit options soon? Can I help you on that?