zframe.c: fix type error in selftest

gcc version 4.8.2 gives:
zframe.c:708:5: error: large integer implicitly truncated to unsigned type [-Werror=overflow]
     size_t test_64bit = 0xFFFFFFFFFFFFFFFF;
czmq_prelude.h/safe_malloc(): C++-robustify the signature

silences "deprecated conversion from string constant to ‘char*’ [-Wwrite-strings]"
Merge pull request #379 from mhaberler/master

remove some nits
created working cmake build for czmq
missing CZMQ_EXPORT for two unit tests
added msvc support for cmake build
added CZMQ_EXPORT to the gsl source
Moved the CMakeLists.txt work into build-cmake.gsl.

The build-cmake.gsl now contains all the new CMake build smarts,
and has GSL rules to explicitly generate the sources and headers list.
The checked in CMakeLists.txt is now generated from build-cmake.gsl.
Merge pull request #380 from guruofquality/cmake_work

created working cmake build for czmq
Fix memory leaks
Merge pull request #382 from HughPowell/master

Fix memory leaks
Fix zlist_dup
Merge pull request #383 from HughPowell/master

Fix zlist_dup
Add zlist_freefn
Merge pull request #384 from HughPowell/master

Add zlist_freefn
Added CZMQ bindings
Fixed issue #377
Added zsocket_sendmem back to API