add optional postamble required by .NET multipart requests
use Request.abort() to abort the request when the request has timed-out

This change will affect the behavior of request that has timed-out.
Now when a user is listening for the error event on a request and that request times-out,
The error handler will only be called once. The error given to the callback will be the timeout error.
add test for postAmble
add documentation for preambleCRLF and postambleCRLF to options list and to multipart explanation in README
2.43.0
2.43.1
2.44.0
2.44.1
Merge pull request #1068 from netpoetica/add-post-amble-crlf-option

add optional postamble required by .NET multipart requests
Merge pull request #1076 from seanstrom/bug/callback-called-twice

use Request.abort() to abort the request when the request has timed-out
refactor the constructObject helper to use soc
fix adding soc as a dependency in package json