Update LibSoup version for new WebKit and fix build.

Includes:
* Providing for downloading prebuilt Libsoup instead of building
* Patches for Libsoup bugs
* adjusting the SQLITE_CFLAGS and SQLITE_LIBS to match what LibSoup's
configure looks for.
* Second WebKit patch and some comments about what's needed to build it.
Install GnuTLS from prebuilt tarballs, optionally build from source.

NB: Building from source requires manual intervention as libgpg-error's
ro.po requires conversion from ISO8859-2 to UTF8, which causes a hang.