Clean up of app.h

app.h, generated from app.h_in, has unnecessary code duplication
and isn't a header file (it defines globals, static functions
and doesn't have a header guard, moreover, it has a 'using namespace
std;'). Because of this, a real headerfile that declares the stuff
defined in apps.h was missing leading to even more code duplication:
scattered forward declarations in .cpp files and an often repeated
type of std::map<std::string, px4_main_t>.

This patch moves cmake/qurt/apps.h_in to src/platforms/apps.cpp.in
(with some changes) and removes cmake/posix/apps.h_in.
Then src/platforms/apps.cpp.in is split into src/platforms/apps.cpp.in
and src/platforms/apps.h.in, splitting declarations from definitions.

A typedef is defined for the map (apps_map_type).

The main difference between cmake/posix/apps.h_in and
cmake/qurt/apps.h_in was that the first defined a global 'apps',
while qurt stores the apps in QShell. I opted to get rid of
the global variable (which are in general evil for various reasons)
and used the API of cmake/qurt/apps.h_in where a provided 'apps'
map is initialized with a call to init_app_map. Thus removing
the existing code duplication.

src/platforms/posix/main.cpp

@@ -48,6 +48,8 @@
 #include <stdio.h>
 #include "apps.h"
 #include "px4_middleware.h"
+#include "px4_posix.h"
+#include "px4_log.h"
 #include "DriverFramework.hpp"
 #include <termios.h>
 #include <sys/stat.h>
@@ -191,6 +193,14 @@ static void print_prompt()
 
 static void run_cmd(const vector<string> &appargs, bool exit_on_fail, bool silently_fail = false)
 {
+	static apps_map_type apps;
+	static bool initialized = false;
+
+	if (!initialized) {
+		init_app_map(apps);
+		initialized = true;
+	}
+
 	// command is appargs[0]
 	string command = appargs[0];
 
@@ -217,7 +227,7 @@ static void run_cmd(const vector<string> &appargs, bool exit_on_fail, bool silen
 		}
 
 	} else if (command.compare("help") == 0) {
-		list_builtins();
+		list_builtins(apps);
 
 	} else if (command.length() == 0 || command[0] == '#') {
 		// Do nothing