Fix build

[aochagavia]

cc iron/iron#143

Note: I wasn't able to build this locally... Cargo yelled the following at me:

Compiling content_type v0.1.0 (https://github.com/reem/rust-http-content-type.git#635e92b7)
Running ./generate
Failed to run custom build command for `content_type v0.1.0 (https://github.com/reem/rust-http-content-type.git#635e92b7)`
Could not execute process `./generate` (status=never executed)

Caused by:
  file not found (OS Error 2: The system cannot find the file specified.)

I guess this has something to do with the fact that I am on Windows.

[aochagavia]

Blocked by iron/iron#180

[reem]

@aochagavia Awesome work! Are you on windows? If so, that might be why rust-http-content-type fails to build for you.

[reem]

Just merged iron/iron#181 so restarting travis on this.

[reem]

Still some bugs. There appears to be a problem with iron-test as well, so will try to fix that soon.

[reem]

@aochagavia Any updates on this? I've fixed all the dependencies.

[aochagavia]

I have accidentally deleted the repository where this branch was. I have forked it again and uploaded the branch with the changes, but GitHub doesn't know it is the same one, so I will need to open a new PR.

However, the build is failing because of replace-map, with a compile error.