[1.4.x] Fixed geos test to prevent random failure

Points in the test fixtures have 20 as max coordinate.

Backport of 87854b0bdf354059f949350a4d63a0ed071d564c from master.
[1.4.x] Bump version post-release.
[1.4.x] Cleaned up 1.4.8 release notes

Backport of 8d29005524 from master
Revert "[1.4.x] Ensure that passwords are never long enough for a DoS."

This reverts commit 3f3d887a6844ec2db743fee64c9e53e04d39a368.

This fix is no longer necessary, our pbkdf2 (see next commit) implementation
no longer rehashes the password every iteration.
[1.4.x] Fixed #21138 -- Increased the performance of our PBKDF2 implementation.

Thanks go to Michael Gebetsroither for pointing out this issue and help on
the patch.

Backport of 68540fe4df44492571bc610a0a043d3d02b3d320 from master.
[1.4.x] Fixed #21248 -- Skipped test_bcrypt if no py-bcrypt found

Pre 1.6 Django worked only with py-bcrypt, not with bcrypt. Skipped
test_bcrypt when using bcrypt to avoid false positives.

Backpatch of 9f8a36eb20895d9e542820d5190bfa77ad1b85d9 from stable/1.5.x.
[1.4.x] Fixed #21256 -- Error in datetime_safe.datetime.combine.

Backport of d9b6fb8 from master
[1.4.x] Fixed #21253 -- PBKDF2 with cached HMAC key

This gives a 2x speed increase compared to the existing implementation.

Thanks to Steve Thomas for the initial patch and Tim Graham for finishing it.

Backport of 1e4f53a6eb8d1816e51eb8bd8f95e704f6b89ead from master.
[1.4.x] Added 1.4.9 release notes

Backport of 2eb8f15516 from master
Fixed #13245: Explained Oracle's behavior w.r.t db_table
and how to prevent table-name truncation

Thanks russellm & timo for discussion, and timo for review.

Backported from master 317040a73b77be8f8210801793b2ce6d1a69301e
[1.4.x] Bumped release date for 1.5.5 & 1.4.9.

Backport of 4ce5c119b5 from master
[1.4.x] Bump everything for 1.4.9 bugfix release.
Making the assumption that joins and relations will be multicolumn
Centralize where we access how columns are related in foreign objects
Adding foreignkeyex which adds ability to add more related fields on foreign objects