solver is dead and gone

Change-Id: I66257ed063849fde997ff78b8b9a6fc2db939fde

README.solver

-solver means "Solar Version", a weird name with only historical significance now
-
-It has no relation to the verb "to solve".
-
-solver is the directory tree into which header files for inter-module
-use and build results (libraries, shared libraries, executables) are
-copied ("delivered") during the build, and from where they are then
-picked up when constructing an installer (Windows), a RPM or deb
-package (Linux) or an app bundle (Mac).