added Buffer "class" based on openssh/buffer.c, which is a really beautiful idea. I'll use this for file i/o and data handling

tests/buffertest.c

@@ -0,0 +1,58 @@
+#include "buffertest.h"
+
+int main() {
+  Buffer *test = buffer_new(16, "test");
+
+  byte *a = ucmalloc(32);
+  byte *b = ucmalloc(32);
+  memset(a, 'A', 32);
+  memset(b, 'B', 32);
+
+  fprintf(stderr, "initial\n");
+  buffer_info(test);
+
+  int i;
+  for(i=0; i<2; i++) {
+    fprintf(stderr, "\nadding As\n");
+    buffer_add(test, a, 32);
+    buffer_info(test);
+    buffer_dump(test);
+
+    fprintf(stderr, "\nadding Bs\n");
+    buffer_add(test, b, 32);
+    buffer_info(test);
+    buffer_dump(test);
+  }
+
+  free(a);
+  free(b);
+
+
+  size_t x;
+  size_t bs = buffer_size(test);
+  void *g = ucmalloc(32);
+  for(x=0; x < bs; x+=32) {
+    fprintf(stderr, "before get\n");
+    buffer_info(test);
+    if(buffer_get(test, g, 32) > 0) {
+    fprintf(stderr, "after get\n");
+      buffer_info(test);
+      _dump("got", g, 32);
+    }
+    fprintf(stderr, "\n");
+  }
+
+  buffer_extract(test, g, 28, 38);
+  _dump("extracted", g, 10);
+
+  uint8_t c = buffer_last8(test);
+  fprintf(stderr, "last byte: %c\n", c);
+
+  free(g);
+
+  buffer_free(test);
+
+  fatals_ifany();
+
+  return 0;
+}