Qcommandlineparser (#199)

* Replaced getoptplusplus with QCommandLineParser. Fixes #39

* enabling C++11 if possible

* enabling C++11 if possible

* fixed gcc compilation issues

* fixed linux builds and improved os x build

* trying to fix dispmanx

* trying to fix dispmanx

* simplified travis build script

* fixed argumentparser default values

* rewrote validator system and made sure default arguments are processed correctly

* rewrote validator system and made sure default arguments are processed correctly

* fixed bool vs. regular options

* oops... removing debug code

* reverted screenshot api change

libsrc/commandline/DoubleOption.cpp

@@ -0,0 +1,20 @@
+#include "commandline/DoubleOption.h"
+#include "commandline/Parser.h"
+
+using namespace commandline;
+
+double DoubleOption::getDouble(Parser &parser, bool *ok)
+{
+    _double = value(parser).toDouble(ok);
+    return _double;
+}
+
+double *DoubleOption::getDoublePtr(Parser &parser, bool *ok)
+{
+    if (parser.isSet(this)) {
+        getDouble(parser, ok);
+        return &_double;
+    } else {
+        return nullptr;
+    }
+}