Fix change_column always executing as as400

When changing defaults or null, queries were always being executed as
as400 regardless of the config setting.
Fix crasher regression on dump of primary keys

Updated primary key dump routine with regards to changes introduced in
6c44f8798b29fc98144cbb5978d7e3194b41f6a0.
Fix name clash obscuring db2_schema method
Fix BSD license text and references

fixes #216.
Merge branch 'master' of github.com:jruby/activerecord-jdbc-adapter
mssql has a README.rdoc file
Merge pull request #222 from bkulyk/master

fix error preventing me from running any rake tasks.
Update hsqldb.jar to 2.2.9
Fix binary data quoting
Merge pull request #226 from jbarreneche/update-hsqldb

Update hsqldb.jar to 2.2.9
Merge pull request #213 from sharplet/master

Fixes to DB2 adapter: change_column and structure_dump
Fix test cleanup for h2 adapter
Use updated postgres string escaping for byte arrays.

Switching to using E'\\000'::bytea rather than just '\\000' when
escaping byte arrays.  Old syntax wasn't supported at all in 9.1,
and new is supported as far back as 8.2.
Minor changes to for travis build
Update appraisal gemfiles
Tweak build settings
Further build tweaks
Couple minor changes for h2/hsqldb

 * Update h2 driver to 1.3.168
 * Fix test_string_id by returning 0 from last_insert_id if
   CALL IDENTITY() returns null.
Fix test errors due to nil ActiveRecord::Base.logger
Scope a few more tests to only ActiveRecord 3+ to fix rails23 build