COMP: Add missing include when building Slicer extension.

Change-Id: I07afe7d8f9a81b4a86aafc7b162f1ce66f1bb911
COMP: Add -fPIC to with TubeTK_BUILD_SLICER_EXTENSION.

Link with shared libraries on amd64.

Change-Id: I9deb0f771e70381194eedf52ea789398819021ce
Merge pull request #116 from thewtex/Slicer-module

Slicer module