Simplify release script
The current release script "releaseSilecs.sh" is by far to complex and error-prone.
It is not required to automatically create branches and tags. Or to push them automatically.
As well having smylinked packages if nothing changed is just an unnecesary extra-level of complexity.
Instead, just provide a single Makefile which just installs all the stuff into the default directory on "make install". Version number is specified in the makefile. Package-specific scripts install.sh might be re-used.
