should search plugins in /usr/local and in HOME directory

[Sergio Costas]

I'm working on a plugin for scratch and found that they must be installed exactly in the same $CMAKE_INSTALL_PREFIX used when compiling the program. This is not good because when installing scratch from a .DEB package it will search only in /usr/lib/scratch/plugins/, so the ones in /usr/local/lib/scratch/plugins/ (the default folder where an script manually compiled by the user will be installed) won't be found.

Also it would be interesting to be able to install plugins in the user's folder ($HOME/.local/lib/scratch/plugins/), allowing users to use new plugins even if they don't have root access.

I attach a patch that fixes this.

[Sergio Costas (rastersoft-gmail)]

Another patch. This one, instead of adding /usr/lib/scratch/plugins and /usr/local/lib/scratch/plugins only when the user installs scratch in /usr or in /usr/local, adds both always. Choose the one you think will adapt better.