Code quality: renamed "backend/" folder to "kernels". More explicit and no longer conflicts with "driver/"

lib/kernels/stream.cpp

@@ -0,0 +1,38 @@
+#include "isaac/kernels/stream.h"
+
+namespace isaac
+{
+
+kernel_generation_stream::kgenstream::kgenstream(std::ostringstream& oss,unsigned int const & tab_count) :
+  oss_(oss), tab_count_(tab_count)
+{ }
+
+int kernel_generation_stream::kgenstream::sync()
+{
+  for (unsigned int i=0; i<tab_count_;++i)
+    oss_ << "    ";
+  oss_ << str();
+  str("");
+  return !oss_;
+}
+
+kernel_generation_stream::kgenstream:: ~kgenstream()
+{  pubsync(); }
+
+kernel_generation_stream::kernel_generation_stream() : std::ostream(new kgenstream(oss,tab_count_)), tab_count_(0)
+{ }
+
+kernel_generation_stream::~kernel_generation_stream()
+{ delete rdbuf(); }
+
+std::string kernel_generation_stream::str()
+{ return oss.str(); }
+
+void kernel_generation_stream::inc_tab()
+{ ++tab_count_; }
+
+void kernel_generation_stream::dec_tab()
+{ --tab_count_; }
+
+}
+