2013-05-05	Timo Bingmann
	* btree.h: changing find_lower() to not use binary search for
	small node sizes. More about this on my blog.
	* btree.h: implementing bulk_load() to construct a B+ tree from a
	pre-sorted iterator range.
	* btree.h: replacing copy loops with std::copy calls.
	* btree.h: added template parameter UsedAsSet to skip copying of
	one byte value_type arrays in set container specializations.
	* license: changing template header source code license to Boost
	License, and the rest to GPLv3.
	* memprofile: using malloc_count to create a memory profile of map
	containers.
	* speedtest: many changes to also include tr1::unordered_set and
	to run both map and set container tests.
	* testsuite: removing cppunit and using enclosed tpunit++ instead.

2011-05-17	Timo Bingmann
	* speedtest: added results of new speed test run in 2011 and also
	appended notes to old speed test doxygen page.

2011-05-06	Timo Bingmann
	* btree.h, others.h: implementing erase(iterator) using recursive
	depth first search for the referenced leaf node.

2011-05-03	Timo Bingmann
	* btree.h: Correcting documentation of lower_bound() and
	upper_bound(). The functions themselves were correct.
	* btree.h: Applying STL allocator patch contributed by MH.
	* btree.h: Correcting limits of for loop to shift pairs from leaf
	to right leaf nodes during deletion.

2008-09-07	Timo Bingmann
	* speedtest.cc: Modifying speedtest to also test the hash table
	container implementation from __gnu_cxx. Extending tests by
	another set of runs measuring only the find/lookup functions.

2008-09-03	Timo Bingmann
	* btree.h: Fixing crash when running verify() on an empty btree
	object. Now the root node is freed when the last item is
	removed. Also fixing crash when attempting to copy an empty btree
	or when trying to remove a non-existing item from an empty btree.

2008-08-13	Timo Bingmann
	* btree.h: Replacing many / 2 integer divisions with >> 1 as
	suggested by received e-mails. This may or may not improve
	speed. I personally doubt it, because modern compilers should
	optimize these simple instructions.

2008-08-01	Timo Bingmann
	* btree.h: Completely reworked reverse_iterator classes. Now they
	are real implementations and do not use STL magic. Both
	reverse_iterator and const_reverse_iterator should work as
	expected now. Added two large test cases for iterators. Also
	enabling public Default-Constructor on iterators.

2008-08-01	Timo Bingmann
	* btree.h: Fixing up a memory access bug which happens in
	leaf->slotkey[leaf->slotuse - 1] if leaf-slotuse == 0. This doesnt
	have any other bad effect, because the case only occurs when leaf
	== root and thus the btree_update_lastkey message is never really
	processed. However it still is a bad-memory access.

2008-01-25	Timo Bingmann
	* btree.h: Fixed a valgrind-detected bug based on a new test case
	received via email. During the find() function find_lower() is
	called and returns the slot number with the smallest or equal
	key. However if the queried key is larger than all keys in a leaf
	node or in the whole tree, find_lower() returns a slot number past
	the last valid key slot. Comparison of this invalid slot with the
	queried key then yields an uninitialized memory error in valgrind.

2007-05-12	Timo Bingmann
	* btree.h: Fixed segfault in print() because of non-existing root.
		   Fixed segfault in end() when the tree is totally empty.
		   Added BTREE_FRIENDS macro so that wxBTreeDemo can
		   access private members.
		   Changing print function to output to a user-given
		   std::ostream