Better consistency across CMakeLists by fixing indentation

Also make use of return() statement in carreraslice_wrap/Widgets
CMakeLists.txt. Doing, the indentation of the CMake code building
the library is similar to what the final implementation would be
(without the conditional building).
Fix windows build error by consistently using std::cout / std::endl

Additionally calling "using namespace std;" is considered bad practice.
See [1] for more details.

[1] http://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice?answertab=votes#tab-top

//------
Windows build error was:

  1>..\..\..\CarreraSlice\src\sfm_local_chanvese\src\interactive_kurvolver.cpp(140) : error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'std::string' (or there is no acceptable conversion)
  1>        C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\include\ostream(653): could be 'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const char *)' [found using argument-dependent lookup]
  1>        with
  1>        [
  1>            _Elem=char,
  1>            _Traits=std::char_traits<char>
  1>        ]
  [...]
//------