Merge branch 'cpp-btree' into jgrpp

src/3rdparty/cpp-btree/README

@@ -35,7 +35,7 @@ cmake . -G "Unix Makefiles" -Dbuild_tests=ON -DCMAKE_CXX_COMPILER=clang++
 Note that this is a modified version of the original at http://code.google.com/p/cpp-btree
 
 Changes include:
-- Changing size_type from ssize_t to size_t
+- Changing size_type from ssize_t to size_t, remove remaining uses of ssize_t
 - Adding cbegin, cend, crbegin, crend.
 - Adding key_comp
 - Adding move constructors/assignment.

src/3rdparty/cpp-btree/btree.h

@@ -886,7 +886,7 @@ class btree : public Params::key_compare {
   };
 
   struct node_stats {
-    node_stats(ssize_t l, ssize_t i)
+    node_stats(size_t l, size_t i)
         : leaf_nodes(l),
           internal_nodes(i) {
     }
@@ -897,8 +897,8 @@ class btree : public Params::key_compare {
       return *this;
     }
 
-    ssize_t leaf_nodes;
-    ssize_t internal_nodes;
+    size_t leaf_nodes;
+    size_t internal_nodes;
   };
 
  public: