The C++ standard does the right thing by default.

This now seems to pass all test cases. Can probably be cleaned up
and optimized a bit more.

Start fixing QMultiHash, requires more work.

And some small cleanup for keys() and values().

Avoid holes in the bucket list to make the hash stable for
long term insertions/erases.

This makes the whole table stable with regards to continuous
inserts/deletes.

Add a test case for a hash with continuous inserts/removals.

We need to remember the deleted bucket, to be able to break out of the loop

Fix errors in QMultiHash::erase() and add equal_range() methods.
Move the growth policy into the QHashPrivate namespace.

And a smaller cleanup when calling insert(QHash).

Inline code into class definition, add some typedefs
for STL compatibility.

It doesn't seem to make a difference in performance

This requires the prepend optimization for QVector

Extend it to 48 bits for 64 bit platforms, and properly handle
the limits on 32 bits.

Avoids a spike in memory usage while rehashing.

use if for integer and pointer based keys, as they don't
have very good hashing functions and often a quite uneven
distribution.