fd files should be lower case

[davidcarlisle]

with pdflatex on case sensitive file systems the package produces

LaTeX Font Warning: Font shape `U/simpleiconsOneZero/m/n' undefined
(Font)              using `U/cmr/m/n' instead on input line 4.


LaTeX Font Warning: Font shape `U/simpleiconsOne/m/n' undefined
(Font)              using `U/cmr/m/n' instead on input line 5.

and uses cmr10 so no icons.

latex produces the .fd filename by lowercasing the encoding and family so it looks for usimpleiconsone.fd but does not find it. Simply renaming the file works although also changing \ProvidesFile{usimpleiconsOne.fd} to match would be better