Expose more CUPS options via the 'Properties' dialog

On systems with CUPS support users can now choose how many pages from
a document are to be printed on paper. This can vary from 1 page per
document to 16 pages per document.

The page preview changes upon the users selection.

Also included in the patch is an option to choose the flow for text.
Users
can now print documents in the "Right to Left" order or "Bottom to Top",
including many other options.

[ChangeLog][QtPrintSupport][QPrintDialog] Added support for setting CUPS
Pages Per Sheet and Pages Per Sheet Layout options

Change-Id: I4e60a4523c6e06d4c15fe9ee9590248fa7ae2038
Reviewed-by: John Layt <jlayt@kde.org>
Check if Print Properties dialog was shown before accessing it

Prevents a crash in case the user did not open
the properties dialog, in which case
QUnixPrintWidgetPrivate::propertiesDialog is null.

Change-Id: I43c8c6ab90053757835bbf41d6167204d42efcef
Reviewed-by: John Layt <jlayt@kde.org>
Android: Added JNI_OnLoad to QtCore

JNI_OnLoad is called for each library during the start-up of a Qt
application on Android. When the JNI_OnLoad is called we can get a
handle to the Java VM and necessary classes which enables us to access
Java API's in QtCore.

Change-Id: I64c1f1106cc0d5ab5a7bc9b22c752c09162fe813
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Android: Add private API for jni in QtCore

When interfacing with Java API's on Android we need to write code using
the Java Native Interface (JNI). Writing JNI code requires a lot of
boilerplate code to be written. This patch contains API's to minimize the
amount of work needed to write JNI code.

QJNIEnvironmentPrivate:
 On creation QJNIEnvironmentPrivate will attach the current running
 thread to the Java VM, and expose the java environment.

QJNIObjectPrivate:
 Wrapps around a Java class enabling the user to access the class from C++.

Change-Id: Ib633437ae36ff513d934292e9eeefcdd5b757d29
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Change QT_FILE_SELECTORS to be comma separated

It is not full paths being used, so switching to comma does not require
different environment variables per platform nor does it appear to be
platform dependent.

Change-Id: I219517d740fa7385e923a9e09cb7e241378f85ba
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: David Faure <david.faure@kdab.com>