setting SOVERSION to 5

[Jonathan Riddell]

In the tech preview release the libraries were all versioned 5.0.0
with SOVERSION of 5.  In alpha 1 that became 4.96.0 with SOVERSION of
4.  The SOVERSION will presumably go back to 5 at some point before
release.  It's quite hassleful to packagers to keep changing the
SOVERSION so I propose changing it back to 5 now.

This means changing the cmakelists files to add an explicit soversion...

set(KF5_VERSION "4.96.0")
ecm_setup_version(${KF5_VERSION} VARIABLE_PREFIX KCONFIG
                        VERSION_HEADER "${CMAKE_CURRENT_BINARY_DIR}/kconfig_version.h"
                        PACKAGE_VERSION_FILE "${CMAKE_CURRENT_BINARY_DIR}/KF5ConfigConfigVersion.cmake"
                        SOVERSION 5)

Shall I do this change to the frameworks?

Jonathan