UseJava.cmake: simplify path logic

Move logic to determine relative path to .java file to after the file
extension check, so that it only executes when it is actually used.
UseJava.cmake: fix passing jars to add_jar

Fix setting classpath when encountering a jar argument to add_jar to
actually set the variable that is used to specify the classpath to
javac, instead of just uselessly appending the jar to
CMAKE_JAVA_INCLUDE_PATH (which is never used again at the point where it
is modified). Also, list jars so specified as dependencies of compiling
the java sources for the jar target.
UseJava.cmake: accept jar targets in add_jar

Modify add_jar to also accepts jars by target name.
Fix cmGeneratorExpression::Preprocess for interleaved inputs.

We can't find both preprocessing expressions at once, because then
the BUILD_INTERFACE will always be favored if both are present, even
if INSTALL_INTERFACE appears first.

This was affecting the behavior of install(EXPORT) because the
INTERFACE_INCLUDE_DIRECTORIES contained entries like

 /foo/include;$<INSTALL_INTERFACE:/bar/include>

As the INSTALL_INTERFACE always evaluates to '0', it always needs
to be preprocessed properly.
FindRuby: improve version selection

This will stop e.g. looking for a ruby1.9 executable first if "1.8 EXACT" was
given.
FindImageMagick: Search versioned suffixes (#14012)

The parent commit added suffixes for -Q8 and -Q16 but there may also be
versioned suffixes -6.Q8 and -6.Q16.
cmake-gui: Use the QStandardItemModel workaround until 5.1.0.

If there is a Qt 5.0.3 release, it may or may not contain the patch
that fixes this issue.

 http://thread.gmane.org/gmane.comp.lib.qt.releasing/882

Just use the workaround until 5.1.0 which certainly will contain the
fix. Don't use the workaround before Qt 5.0.0.
Merge topic 'fix-java-jar-depends'

adeafad UseJava.cmake: accept jar targets in add_jar
53a05b8 UseJava.cmake: fix passing jars to add_jar
45c8e4b UseJava.cmake: simplify path logic
Merge topic 'fix-genex-preprocess'

7a619fa Fix cmGeneratorExpression::Preprocess for interleaved inputs.
Merge topic 'Ruby-version-selection'

d7e05e4 FindRuby: improve version selection
Merge topic 'FindImageMagick-v6.8.0-8'

dbd895b FindImageMagick: Search versioned suffixes (#14012)
Merge topic 'expand-version-of-Qt5-gui-fix'

6387f6d cmake-gui: Use the QStandardItemModel workaround until 5.1.0.