Added optional '=' to MySQL KEY_BLOCK_SIZE regex
Posgtresql -> PostgreSQL
- Fixed some "double invalidate" situations were detected where
a connection invalidation could occur within an already critical section
like a connection.close(); ultimately, these conditions are caused
by the change in :ticket:`2907`, in that the "reset on return" feature
calls out to the Connection/Transaction in order to handle it, where
"disconnect detection" might be caught.  However, it's possible that
the more recent change in :ticket:`2985` made it more likely for this
to be seen as the "connection invalidate" operation is much quicker,
as the issue is more reproducible on 0.9.4 than 0.9.3.

Checks are now added within any section that
an invalidate might occur to halt further disallowed operations
on the invalidated connection.  This includes two fixes both at the
engine level and at the pool level.   While the issue was observed
with highly concurrent gevent cases, it could in theory occur in
any kind of scenario where a disconnect occurs within the connection
close operation.
fixes #3043
ref #2985
ref #2907

- add some defensive checks during an invalidate situation:
1. _ConnectionRecord.invalidate might be called twice within finalize_fairy
if the _reset() raises an invalidate condition, invalidates, raises and then
goes to invalidate the CR.  so check for this.
2. similarly within Conneciton, anytime we do handle_dbapi_error(), we might become invalidated.
so a following finally must check self.__invalid before dealing with the connection
any futher.
- stress test for invalidation
- Fixed ORM bug where the :func:`.class_mapper` function would mask
AttributeErrors or KeyErrors that should raise during mapper
configuration due to user errors.  The catch for attribute/keyerror
has been made more specific to not include the configuration step.
fixes #3047
Documentation fix-up: "its" vs. "it's"

Removed ungrammatical apostrophes from documentation, replacing
"it's" with "its" where appropriate (but in a few cases with "it is"
when that read better).

While doing that, I also fixed a couple of minor typos etc.
as I noticed them.
Merge pull request #91 from smurfix/de_apostroph_ify

Documentation fix-up: "its" vs. "it's"
Merged in WSMcG/sqlalchemy (pull request #15)

Added optional '=' to MySQL KEY_BLOCK_SIZE regex
changelog for pullreq bitbucket:15
Merged in mineo/sqlalchemy/mineo/posgtresql-postgresql-1399232068499 (pull request #17)

Posgtresql -> PostgreSQL
pg8000.dbapi is now just pg8000
pg8000 no longer truncates decimals

We can now update the requirements to remove the special case of pg8000
truncating decimals.
Two tests now work for pg800 in EnumTest

The two tests, test_create_table() and test_unicode_labels() previously
failed under pg8000, but now they pass, so this commit opens them up.
pg8000 now passes test_extract() test
Add postgresql+pg8000 to floats_to_four_decimals

pg8000 uses binary transfer of floats and so accuracy is lost for floats
that can't be represented exactly in binary.