update exec_xxx tests for DBs that do not generate IDs (Oracle, Firebird)
update test_exec_insert so it's more 'portable' with formatted time values
aling MSSQL's exec_xxx overrides with base implementation
use record.class.connection instead of record.connection (now deprecated)
[oracle] make sure explain works with prepared statements
update jTDS to 1.3.1
review HSQLDB/H2 explain - make sure prepared statements are used
update H2 database to 1.3.173
update HSQLDB to 2.3.0
delay connection.getMetaData esp. with queries, changes some signatures
esp. caseConvertIdentifierForJdbc/Rails to accept a connection (see #453)
avoid connection.getMetaData on Oracle with exec_query (fixes #453)

Oracle seems to be doing some SQL on getMetaData ... this seems to improve performance singnificantly: test run times :

before: 185-190s / 180 PS
   after:  130-150s / 125 PS
MySQL does not store upper-case identifiers (for lower case it depends)
we shall not wait for AR to type-cast `'true'` configuration value into `true`
improve `drop_table` on Oracle (falsy sequence_name menas no sequence)
[oracle] fix structure_dump: `column['data_default']` might come back as ''
Java API make sure we call (the overridable) extractColumns (due MSSQL)
create MySQL test db with utf8_general_ci collation
re-build jar (compiled using jruby 1.6.8 on java 6) for 1.3.0 release
update README (for 1.3.0 stable)