[qtcontacts-sqlite] Remove Qt4 support

After this change, the engine can be built only with qt5 and qtpim.
[qtcontacts-sqlite] Remove QContactIdType typedef

This typedef was only used to mitigate differences between qtpim and
QtMobility Contacts interfaces.
[qtcontacts-sqlite] Remove SKIP_TEST definition

This macro was only used to mitigate differences between qt4 and qt5.
Merge pull request #104 from matthewvogt/remove-qt4

Remove qt4 support