CONTENT_LENGTH and CONTENT_TYPE parameters are reflected as headers nt-length and nt-type

[fbbdev]

There is a bug in node-fastcgi/lib/request.js, line 281..
CONTENT_LENGTH and CONTENT_TYPE are renamed in the header as nt-length and nt-type due to the slice(5).

First reported in #14
Introduced in version 1.1.0, commit 50d3d6a