Use http-conduit for url downloads by default, annex.web-options enables curl

* For url downloads, git-annex now defaults to using a http library,
  rather than wget or curl. But, if annex.web-options is set, it will
  use curl. To use the .netrc file, run:
    git config annex.web-options --netrc
* git-annex no longer uses wget (and wget is no longer shipped with
  git-annex builds).

Note that curl is always run in silent mode, since the new API for
download has a MeterUpdate and doesn't make way for curl progress
output. It might be worth writing a parser for curl's progress output
to update the meter when using it, but I didn't bother with this edge
case for now.

This commit was supported by the NSF-funded DataLad project.

debian/control

@@ -83,7 +83,6 @@ Build-Depends:
 	libimage-magick-perl,
 	git (>= 1:1.8.1),
 	rsync,
-	wget,
 	curl,
 	openssh-client,
 	git-remote-gcrypt (>= 0.20130908-6),
@@ -101,7 +100,6 @@ Section: utils
 Depends: ${misc:Depends}, ${shlibs:Depends},
 	git (>= 1:1.8.1),
 	rsync,
-	wget,
 	curl,
 	openssh-client (>= 1:5.6p1)
 Recommends: