title: Missing dependency when building with CMake
body: <p>I'm trying to build the <a href="https://github.com/ivansafrin/Polycode" rel="nofollow">Polycode</a> codes using CMake. I followed the instructions in the <a href="https://github.com/ivansafrin/Polycode/blob/master/BUILD.md" rel="nofollow">Build.md</a> file, but I get the following error:</p>
  
  <pre><code>$ cmake -G "Visual Studio 10" ..
  No POLYCODE_RELEASE_DIR specified, to C:/Development/Polycode/Release/Windows
  DEBUG CMAKE_PREFIX_PATH=C:/Development/Polycode/Release/Windows/Framework/Core/Dependencies;C:/Development/Polycode/Release/Windows/Framework/Modules/Dependencies;C:/Development/Polycode/Release/Windows/Framework/Tools/Dependencies
  CMake Error at c:/Program Files (x86)/CMake 2.8/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:97 (message):
    Could NOT find ZLIB (missing: ZLIB_LIBRARY ZLIB_INCLUDE_DIR)
  Call Stack (most recent call first):
    c:/Program Files (x86)/CMake 2.8/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:291 (_FPHSA_FAILURE_MESSAGE)
    c:/Program Files (x86)/CMake 2.8/share/cmake-2.8/Modules/FindZLIB.cmake:85 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
    CMake/PolycodeIncludes.cmake:14 (FIND_PACKAGE)
    Core/Contents/CMakeLists.txt:2 (INCLUDE)
  
  
  -- Configuring incomplete, errors occurred!
  </code></pre>
  
  <p>I see that it needs ZLIB but, I don't know how to handle this. Shouldn't it download the dependency automatically? I could surely find ZLIB and download it but I don't really want to do this with every single lib it might need. Is there a convenient way to solve this?</p>