fix(unity): GridFire supports unity builds

GridFire can now support unity builds. This is useful for python
bindings. The main limitation is that openssl (a dependency of
libplugin) does not support unity builds. Therefore when building in a
unity build libplugin must be disabled. This is done with the
-Dunity-safe=ture flag at setup time

pyproject.toml

@@ -8,7 +8,7 @@ build-backend = "mesonpy"
 
 [project]
 name = "gridfire"  # Choose your Python package name
-version = "0.7.3_rc2" # Your project's version
+version = "0.7.4_rc2" # Your project's version
 description = "Python interface to the GridFire nuclear network code"
 readme = "README.md"
 license = { file = "LICENSE.txt" } # Reference your license file [cite: 2]