#145 pymol svn produces many warnings with -Wunused-function and -Wunused-variable

[Jack Howarth]

The build of pymol svn with Clang 5.0 using -Wall produces a rather large number of warnings from -Wunused-function and -Wunused-variable. Since pymol is built as shared modules this code can't be pruned with the dead-code elimination at -O4. This dead code should either be removed or wrapped with preprocessor conditionals to avoid compiling it.