Create a constructor with default parameters for some structs

Structs and classes in C++ are basically the same thing and we want to
create a few zero-initialized values for some of them; Sadly, C++ doesn't
have the nice static struct initialization that C has.

One way to deal with that is to create a constructor and pass default
values to it, another is lambda-initialization, but we don't use C++11,
yet.

Since we initializate stuff on the constructor, we don't need to
re-initializate things again on the initialization list (which is also why
I removed the QStrings from the initialization lists, they are
automatically initialized to empty)

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

subsurface-core/devicedetails.cpp

@@ -1,32 +1,19 @@
 #include "devicedetails.h"
 
-// This can probably be done better by someone with better c++-FU
-const struct gas zero_gas = {0};
-const struct setpoint zero_setpoint = {0};
+gas::gas(unsigned char oxygen, unsigned char helium, unsigned char type, unsigned char depth) :
+	oxygen(oxygen), helium(helium), type(type), depth(depth)
+{
+}
+
+setpoint::setpoint(unsigned char sp, unsigned char depth) :
+	sp(sp), depth(depth)
+{
+}
 
 DeviceDetails::DeviceDetails(QObject *parent) :
 	QObject(parent),
 	data(0),
-	serialNo(""),
-	firmwareVersion(""),
-	customText(""),
-	model(""),
 	syncTime(false),
-	gas1(zero_gas),
-	gas2(zero_gas),
-	gas3(zero_gas),
-	gas4(zero_gas),
-	gas5(zero_gas),
-	dil1(zero_gas),
-	dil2(zero_gas),
-	dil3(zero_gas),
-	dil4(zero_gas),
-	dil5(zero_gas),
-	sp1(zero_setpoint),
-	sp2(zero_setpoint),
-	sp3(zero_setpoint),
-	sp4(zero_setpoint),
-	sp5(zero_setpoint),
 	setPointFallback(0),
 	ccrMode(0),
 	calibrationGas(0),