liblion is a subset of RELION 1.4 basic image processing functions that can be compiled and used in Visual Studio projects on Windows. To use it, add the root folder as include dir and #include "src/liblion.h". Link x64/(Debug|Release)/liblion.lib and fftw/libfftw3-3.lib, put libfftw3-3.dll in your runtime directory. All classes and methods are in the relion namespace.

Original RELION readme text:

RELION (for REgularised LIkelihood OptimisatioN) is a stand-alone computer program for Maximum A Posteriori refinement of (multiple) 3D reconstructions or 2D class averages in cryo-electron microscopy. It is developed in the research group of Sjors Scheres at the MRC Laboratory of Molecular Biology. The underlying theory of MAP refinement is given in a scientific publication: Scheres, JMB (2011) (DOI: 10.1016/j.jmb.2011.11.010). If RELION is useful in your work, please cite this paper. 

The documentation of RELION is stored on the following Wiki page:
http://www2.mrc-lmb.cam.ac.uk/relion

The INSTALL.sh script is provided for convenient installation. Please see the above-mentioned Wiki for more information.