I like the idea of this library and besides the mentioned additional use for "relative bundle path code used on Windows and Mac", we probably can move some of the plugin configuration config file handling in each plugin here. There is a lot of duplicated code around.

Since we add a new dependency for other plugins here (currently just Workbench but probably more in the future), we should emphasize this in the NEWS to help distro packagers when releasing. They probably need to add something like geany-plugins-common package and make all other plugin sub packages depend on this (as it is already on Debian).

Apropos, in order to be able to compile it on Windows I had to add: `-no-undefined` to `libgeanypluginutils_la_LDFLAGS`. Without, linking fails with: `can't build shared library unless -no-undefined is specified`. I'm not sure whether we should add it there or better in `build/vars-build.mk` where it is already specified for `AM_LDFLAGS`.