extend FileReadingCollector to support reading from s3

note: since number of readers cannot be set yet and the
"shared module" import functionality is disabled - reading
from s3 will result in duplicate imported rows if there are
more then 1 node in the cluster

this also replaces the PCRE support with globbing support
update the copy from documentation

this commit already documents options which are not yet
available but will be added shortly.
copy from: implement "compression", "shared" and "num_readers" options
fix copy from shared state issue
fix prefix handling in S3FileInput
use HTTP for the S3 connection

using HTTPS results in SSLPeerUnverifiedException.
Merge pull request #671 from crate/copy

add S3 support and more options to COPY FROM