Adaptation to Qt's pimpl idiom design. Improved inheritance safety.

Details:
* Improved unsafe C-style macros inheritance approach to the project-wide
DEFINES: it is unspecified in
which order source files are being preprocessed ones, so in
singleapplication.cpp the class might be inherent of default-specified
base, while in main.cpp this can be a user-provided QAPPLICATION_CLASS
definition.

* Replace Qt's pseudo-keywords to more library-independent counterparts
('emit -> Q_EMIT', etc)

* Indentation fixes (80 character column-width)

* Rearragned #include statements: from most platform-independen to more
app-specific.

* Fixed some grammar typos.

* README.md updated respectively.

1 files changed, 12 insertions, 13 deletions

diff --git a/README.md b/README.md
index 7cf1f9e..754e6b4 100644
--- a/README.md
+++ b/README.md
@@ -3,11 +3,11 @@ SingleApplication
 
 This is a replacement of the QSingleApplication for `Qt5`.
 
-Keeps the Primary Instance of your Application and kills each subsequent instance.
+Keeps the Primary Instance of your Application and kills each subsequent instances.
 
 Usage
 -----
-The `SingleApplication` class inherits from `QApplication`. Use it as if you are using the `QApplication` class.
+The `SingleApplication` class inherits from whatever `Q[Core|Gui]Application` class you specify in the `*.pro` file. Further usage is similar to use one of the `Q[Core|Gui]Application` classes.
 
 The library uses your `Organization Name` and `Application Name` to set up a `QLocalServer` and a `QSharedMemory` block. The first instance of your Application would check if the shared memory block exists and if not it will start a `QLocalServer` and then listen for connections on it. Each subsequent instance of your application would check if the shared memory block exists and if it does, it will connect to the QLocalServer to notify it that a new instance had been started, after which would terminate the new instance with status code `0`. The Primary Instance, `SingleApplication` would emmit the `showUp()` signal upon detecting that a new instance had been started.
 
@@ -15,6 +15,10 @@ The library uses `stdlib` to terminate the program with the `exit()` function.
 
 Here is an example usage of the library:
 ```cpp
+// project.pro
+DEFINES += QAPPLICATION_CLASS=QApplication # or whatever app class you want
+
+// main.cpp
 #include "singleapplication.h"
 
 int main(int argc, char *argv[])
@@ -34,21 +38,16 @@ The SingleApplication class implements a `showUp()` signal. You can bind to that
 
 Note that since `SingleApplication` extends the `QApplication` class  you can do the following:
 ```cpp
-QObject::connect(QApplication::instance(), SIGNAL(showUp()), window, SLOT(raise())); // window is your QWindow instance
+// Truly raise your window.
+QObject::connect(&app, &SingleApplication::showUp, [&]{
+        window.show();
+        window.raise();
+        window.activateWindow();
+    }); // 'window' is your QWindow instance
 ```
 
 Using `QApplication::instance()` is a neat way to get the `SingleApplication` instance at any place in your program.
 
-Extending from other application classes
------------------------
-
-`SingleApplication` extends from the `QApplication` class by default , but you can easily change that to `QGuiApplication` or `QCoreApplication` with the `QAPPLICATION_CLASS` macro. Define it before the include statement of `singleapplication.h` or change the default value in the file.
-
-__Example:__
-
-```cpp
-#define QAPPLICATION_CLASS QCoreApplication
-```
 
 Implementation
 --------------