API in readme, simplify required includes

examples/cpu_turbo.cpp

@@ -3,6 +3,7 @@
 #include "perfect/cpu_turbo.hpp"
 
 int main(void) {
+  perfect::init();
 
   perfect::Result ret;
   perfect::CpuTurboState state;

examples/gpu_clocks.cu

@@ -4,9 +4,7 @@
 #include "perfect/init.hpp"
 
 int main(void) {
-
     using namespace perfect;
-
     init();
 
     for (unsigned int gpu = 0; gpu < 1; ++gpu) {

examples/gpu_turbo.cu

@@ -4,12 +4,11 @@
 #define OR_DIE(expr)
 
 int main(void) {
-
   using namespace perfect;
-  GpuTurboState state;
-
   init();
 
+  GpuTurboState state;
+
   for (unsigned int gpu = 0; gpu < 1; ++gpu) {
     PERFECT(perfect::get_gpu_turbo_state(&state, gpu));
     PERFECT(perfect::disable_gpu_turbo(gpu));

examples/os_perf.cpp

@@ -3,7 +3,7 @@
 #include <map>
 
 int main(void) {
-
+    perfect::init();
 
     std::map<int, perfect::OsPerfState> states;