find_dependency: Don't propagate EXACT argument.

If a package is requested with an EXACT version, that doesn't imply
that dependencies must be found EXACTly too.

Extend the macro to allow specifying that a dependency must be found
by EXACT version instead.
Qt4: Use correct qdbus executable in macro.

Commit v3.0.0-rc1~71^2~9 (Qt4: Use IMPORTED executable names with
custom commands., 2014-01-24) erroneusly changed this command to
use the wrong target.
QtAutogen: Fix AUTOGEN depends on custom command output with VS.

Visual Studio is handled as a special case for autogen depends. However,
the special handling works only for target dependencies, not file
dependencies output by a custom command.

Use a PRE_BUILD step only if all depends are targets.
Merge branch 'fix-Qt4-DBus-macro' into release
Merge branch 'fix-find_dependency-EXACT' into release
Merge branch 'fix-AUTOGEN-custom-command-depends' into release
Help: Document variables CMAKE_APPBUNDLE_PATH and CMAKE_FRAMEWORK_PATH
Merge branch 'doc-osx-path-variables' into release