BuildSystem: Cleanup userspace directory layout

userspace programs are now in userspace/programs
userspace tests are now in userspace/tests

This makes listing userspace projects much cleaner. Libraries were
already separated to their own directory, so other programs should also.

userspace/programs/echo/CMakeLists.txt

@@ -0,0 +1,8 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(echo ${SOURCES})
+banan_link_library(echo libc)
+
+install(TARGETS echo OPTIONAL)

userspace/programs/echo/main.cpp

@@ -0,0 +1,40 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void print_argument(const char* arg)
+{
+	while (*arg)
+	{
+		if (*arg == '\\')
+		{
+			switch (*(++arg))
+			{
+				case 'a': fputc('\a', stdout); break;
+				case 'b': fputc('\b', stdout); break;
+				case 'c': exit(0);
+				case 'f': fputc('\f', stdout); break;
+				case 'n': fputc('\n', stdout); break;
+				case 'r': fputc('\r', stdout); break;
+				case 't': fputc('\t', stdout); break;
+				case 'v': fputc('\v', stdout); break;
+				case '\\': fputc('\\', stdout); break;
+				default: break;
+			}
+		}
+		else
+			fputc(*arg, stdout);
+		arg++;
+	}
+}
+
+int main(int argc, char** argv)
+{
+	for (int i = 1; i < argc; i++)
+	{
+		print_argument(argv[i]);
+		if (i < argc - 1)
+			fputc(' ', stdout);
+	}
+	printf("\n");
+	return 0;
+}