Add information on pohelper plugin in MAINTAINERS
geanyextrasel - added "Toggle Rectangular/Stream"
geanyextrasel - increased version to 0.51
Autotools: define GP_GTK3 as an AM conditional

This allows plugins to have conditionals in their Makefiles depending
on whether they are built against GTK2 or GTK3.
Autotools: honor --with-geany-libdir when checking whether to enable GTK3
GeanyGenDoc: fix a memory leak when saving the configuration
GeanyMiniScript: make the plugin compile against GTK3
Merge pull request #97 from earshinov/geanyminiscript-gtk3

GeanyMiniScript: make the plugin compile against GTK3