Header reorg
Closes #18 (closed)
Header files are moved to separate directories
make install will copy all libraries to INSTALLDIR/palisade/lib and all headers to INSTALLDIR/palisade/include
a CMakeLists.User.txt is provided for users to build their PALISADE applications and refer to the installed headers and libs
All core demos should only need to #include "palisadecore.h"
All pke demos should only need to #include "palisade.h", a header for the scheme (scheme/SCHEMENAME/scheme.h) and, if necessary, the -ser.h files for serializing
@ypolyakov @krohloff FYI