cmake // fixed msvc dll output path

Unable to run test from console (cmd) or msvc ide
<pre>
cmake  &lt; path to libzmq clone &gt;
cmake --build . --config Debug
ctest -VV -C Debug
</pre>
Test execution will fail because dll file is placed into 'lib' folder instead of 'bin'

Fix it by adding target property to place zeromq dll with test binaries.