Include results for all attributes in multipoint shapefiles

[mattwigway]

There's no reason not to include the accessibility results for all attributes in multipoint shapefiles, which will simplify data management outside of analyst for our users.

[mattwigway]

And also all parameters.

[mattwigway]

Unfortunately, this is too slow for production use. I'm going to leave all the code in place so when we make operations with shapefiles faster (see #111) we can just turn it back on.