curl: Initial codedrop of curl-7.21.3.tar.gz

URL: http://curl.haxx.se/download/curl-7.21.3.tar.gz
Enable CURL compilation for Android

Change-Id: I5ccae4b0d83a3d91590c00ef583c21fee7ee0f00
build: Updating LOCAL_MODULE_TAGS with optional tag

Change-Id: I049aef85934dc258fde03b24e64e9fe5f5399d4f
CRs-Fixed: 310616
build: Cleanup/fix usage of ALL_PREBUILT

While working with AOSP latest branch, we found that, the
variable has changed and causing build failures.
To get rid of build failures and to be in sync with AOSP Build
System, we are deprecating the use of the variable.

As the NOTICE file is already in the repository, commenting
the ALL_PREBUILT usage.

Change-Id: Id4ccc4093eafc271c27e9dd1a786844517d58300
CRs-Fixed: 314291
Configuring CURL for HTTPS Support.

This is merely a reconfiguration of CURL to include support for HTTPS.
Until now in the target builds, the CURL does not support HTTPS. Make file
requires the needed modifications to configure the curl library.

Change-Id: Idf0d147fb1c5842405f609ac8519902586172612
Adding makefile and documentation files for curl

Change-Id: I852d0cede1238b27e71a951d2e18563fd3d850c5