Ask whether to save existing project when creating a new
 project from a template.
Fix uses of deprecated Qt methods

There are still a few leftovers from the Qt 3 to Qt 4 migration that can
be found by defining QT_NO_DEPRECATED. Here is a summary of the changes:

* QDir::convertSeparators was changed to QDir::toNativeSeparators with Qt 4

* QRexExp::numCaptures was changed to captureCount with Qt 4

* QTextIStream/QTextOStream was merged into QTextStream with Qt 4

* QFileDialog::selectFilter/filters was changed to
  selectNameFilter/nameFilters with Qt 4.4

* qVariantCanConvert/qVariantValue was changed to canConvert/value with Qt
  4

Note that if a conversion to Qt 5 will happen someday, this will have to
be done since Qt 5 removes these deprecations.
Remove include of QtGui in favor of individual includes

The reason for removing instances of "#include <QtGui>" is twofold:

1) Including it will probably include more than is actually needed. Plus,
   it hide what is actually needed, especially if in a header

2) Qt 5 splits Gui into Gui and Widgets, so being explict about what is
   needed gets around this problem
[processing] show confirmation when closing modeler with unsaved model
(fix #9889)
updated translation pl
updated translation pl
translation update pl
Fix symbol's size/width not being updated in GUI on load
identify and other map tools changed to use search radius in mm
[processing] enable temporary outputs in QGIS Field Calculator (fix #9401)
[processing] move OTB output to INFO tab, fix deprecation warning
[processing] handle non-ASCII characters when running GRASS algorithms
(addresses #5420)
fix #9334
[ftools] use int column for point count (fix #9432)
Make PostGIS provider correctly use time and datetime formats, instead of converting them to character
avoid warning messages on composer arrows without markers
Replace WFlags with WindowFlags

It has long been in Qt 4 that the WFlags window flags argument has been
renamed to WindowFlags. In fact, WFlags is just a typedef to WindowFlags.
In Qt 5, this will go away, so we can change this now to make transition
easier in the future.

This should not have any affect on API or ABI, as the symbol names already
have WindowFlags in them anyway.

This change concentrates on the sources in the src directory. There are
a few more places in the python directory that can be done later.
Change also SIP files to use WindowFlags instead of WFlags
[Plugin manager] Replace confirmation popup dialogs with an internal QgsMessageBar
missing identify/highlight sip methods