legendflex.m: a more flexible, customizable legend

linked GitHub readme

Updated description (which was erased when the github link was added)

- Corrected some remaining R2014b bugs; all graphics handles should now be objects rather than numeric if running in R2014b or later.
- Switched source to github repository

Added note regarding legendflex with the Latex interpreter

Added parameter to modify padding between legend box and text/symbols

- updated for R2014b graphics

Now respects manual changes made by user (including legend height, width, and units) when resizing.

Fixed bug where very wide titles were not completely enclosed in legend box.

bug fixes: fixed error in function resize if you delete the legend, fixed minor vertical alignment issue

Figure resize now re-links legend and labeled objects with updated line/patch properties.