Fix CMake 3.3+ warning on CXX_VISIBILITY_PRESET (and other clean up)

[ssoelvsten]

This fixes the following warning in CMake during compilation.

CMake Warning (dev) at tpie/CMakeLists.txt:224 (add_library):
  Policy CMP0063 is not set: Honor visibility properties for all target
  types.  Run "cmake --help-policy CMP0063" for policy details.  Use the
  cmake_policy command to set the policy and suppress this warning.

  Target "tpie" of type "STATIC_LIBRARY" has the following visibility
  properties set for CXX:

    CXX_VISIBILITY_PRESET

  For compatibility CMake is not honoring them for this target.
This warning is for project developers.  Use -Wno-dev to suppress it.

There are also a few other minor clean ups of the CMake files.