patching examples that use png files from leaflet js site since they have moved.
adding leaf images png files for examples
updated layers control to handle special characters in group name. All non-alphanumeric characters are removed from the class names and javascript selectors.
added better error message for missing color and pal
adding addLegendLine to add height only encoding of size based on values
updated example in README
adding addLegendAwesomeIcon function to produce legends with markers from awesome icon libraries
adding in line and polygon symbol and adding symbols to the README
fixes error on makeSizeLegend where fillColor is not evaluated if no argument is provided
adding colorValues as an argument to makeSizeLegend so that symbols can be sized and colored on different vectors of data
fixes warning on addLegendNumeric where the shape default was a vector not a single value
adding number formatting to addSizeLegend
adding group layer support for legends. Use addLayersControl to turn on/off legends
added example for using raster images with size encodings based on data
stroke outlines of shapes are now padded so that the stroke is not cut off
numeric legends now have appropriate sizing for text
star symbol outline has been fixed
new function makeSizeIcons as a convenience wrapper size scaled symbols
new functions addLegendSize, sizeNumeric, and sizeBreaks were added to allow encoding size on symbols.
addLegendImage supports multiple height and width parameters for images where you want different sizes
addLegendImage now supports using an svg URI from the output of makeSymbol. To supply a custom svg URI, add the ‘svgURI’ class to the character vector.
added more shapes to makeSymbol, addLegendNumeric, addLegendQuantile, addLegendFactor, addLegendBin
Control the opacity of the legend shapes for addLegendNumeric, addLegendQuantile, addLegendFactor, addLegendBin
makeSymbol now returns embeddable svg
NEWS.md file to track changes to the package.