Fix NTL testsuite
Update sqlite to version 3.8.4.3.
Update libpng to version 1.2.51.
Patch Python uuid module to lower side effects when it is imported.

This resolves segfaults on Cygwin64 when building sagenb.
Trac #16098: Update sqlite to 3.8.4.3

Straightforward update it seems.
And this version supports Cygwin64.

Use tarball (renamed and recompressed) at:
* http://boxen.math.washington.edu/home/jpflori/upstream/sqlite-3.8.4.3.
tar.bz2

URL: http://trac.sagemath.org/16098
Reported by: jpflori
Ticket author(s): Jean-Pierre Flori
Reviewer(s): Volker Braun
Trac #16099: Update libpng to 1.2.51

Straightforward update.
Works on Cygwin64.

Use tarball at:
* http://boxen.math.washington.edu/home/jpflori/upstream/libpng-1.2.51.t
ar.gz

URL: http://trac.sagemath.org/16099
Reported by: jpflori
Ticket author(s): Jean-Pierre Flori
Reviewer(s): Volker Braun
Trac #16119: Patch Python uuid module

This prevents "heavy side effects" which include segfaults when building
sagenb on Cygwin64.
See http://bugs.python.org/issue11063.

URL: http://trac.sagemath.org/16119
Reported by: jpflori
Ticket author(s): Jean-Pierre Flori
Reviewer(s): Volker Braun
Trac #16131: Fix NTL's spkg-check

{{{
$ ./sage -f -c ntl
[...]
Successfully installed ntl-6.1.0.p0
Running the test suite for ntl-6.1.0.p0...
./spkg-check: line 9: cd: src/src: No such file or directory

Running NTL's test suite...
make: *** No rule to make target `check'.  Stop.

NTL's test suite passed.
}}}

URL: http://trac.sagemath.org/16131
Reported by: jdemeyer
Ticket author(s): Jeroen Demeyer
Reviewer(s): Volker Braun