Update README.md
No, really, fix the wiki link.
Fix --simplify-proportion argument.
Allow multiple --id-property.
Bump version.
Make Node version dependency explicit.
Use console.log instead of fs.appendFileSync.
Shapefile parsing!

Also, you can now specify the object name for an input file by specifying an
input file of the form "name=path". For example:

  topojson -o us.json -- states=../us-atlas/shp/statep010.shp

Note that the -- is required here to avoid confusing with the bash shell.