Fix the waitForReadyRead() behavior on Windows

It is necessary to compare size of the readBuffer before and after
completion of each read operation. If size of readBuffer are equal
it means that are no more data available for reading. In this case
the method should returns true if an initial size of readBuffer is
not equal to the current size of readBuffer. Otherwise in all other
cases should be continue waiting until timeout has been expired.

Also must not to do check for the NoError code and to hope for valid
value of this code inside waitForReadyRead(). Because a last error
code do not clears automatically. It lead to false returns of this
method in case the error number is not equal to NoError (for example
it error remained after failed of any previous method). This check
should be implemented in a different way in case of need. But at
present this check is unnecessary because result of the waitAnyEvent()
cover it.

Task-number: QTBUG-33987
Change-Id: Ic8d8e3806fd4863c2720ffb83d5c19eae54d57f0
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Reviewed-by: Laszlo Papp <lpapp@kde.org>
Fix the broken handle() documentation

This is likely to be happening due to the mismatching function signature include
the return type between the header and source file. Two things are being fixed:

1) Dropped scope for the Handle just like with the winId case in QWidget.

2) "const" qualifier is now added for the method.

Here you can see the documentation that it is empty:
http://qt-project.org/doc/qt-5/qserialport.html#handle

Change-Id: I5e9e0732cfd746a863de523fe90e58eafa42c081
Reviewed-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Reviewed-by: Martin Smith <martin.smith@digia.com>
Fix the creaderasync example name in the qdoc file

This change eliminates the following warnings when using "make docs":

/home/lpapp/Projects/qt/qt5/qtserialport/examples/serialport/doc/creaderasync.qdoc:28:
warning: Cannot find file 'creader/creader.pro' or 'creader/creader.qmlproject'

/home/lpapp/Projects/qt/qt5/qtserialport/examples/serialport/doc/creaderasync.qdoc:28:
warning:   EXAMPLE PATH DOES NOT EXIST: creader

It is also visible that the example is unreachable on the following
documentation page:

http://qt-project.org/doc/qt-5/examples.html

Change-Id: I09f1532fcff6b1f7bfc5c4857bd14252aceb2eb3
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Refactor the reference in the documentation for property setters/getters

The documentation contains broken links due to this, and it is also inconsistent
with the rest. Properties should be referred to as properties, not individual
methods like setter, getter, notified signal, etc.

The change is tested with "make docs" and the broken links are history.

Change-Id: Id94cba1f88503754318c865793229e3d3947bec6
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Martin Smith <martin.smith@digia.com>
Obsolete the TxD/RxD signals

They are not much of use due to the low-level OS limitations as of now, hence
the obsolete proposal. It can be brought back to life at any point when we have
a more clear idea what to do with this API.

"faking" this signal as RealTterm probably does it, is not a nice impression
for the end users. That would be more like a software "signal" (which we
already have in place) rather than a real pinout hardware signal.

It is interesting why Windows, Linux, etc do not provide an option for this.
There must be some strong reason for it.

Change-Id: Ia065e2ee9226d16e724f5e2690b25b954329d78e
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Merge remote-tracking branch 'origin/release' into stable

Conflicts:
	src/serialport/qserialport_win.cpp

Change-Id: Ib00a645c6660a3c81dbc9e159110f7bfc392ea36