Merge pull request #569 from mpscholten/readonly-tables-import-from

Readonly tables should not have an importFrom method (see issue #543)
Fix getting option value from configuration
return type hint for endUse()
transaction: always return the result of callable
Merge pull request #576 from gharlan/transaction-return-value

transaction: always return the result of the callable
Merge pull request #571 from gharlan/endUse-return-type

return type hint for endUse()
Made Propel HHVM compatible with MySQL.
Merge pull request #561 from marcj/hhvm

Made Propel HHVM compatible with MySQL.
Merge pull request #570 from drodil/master

Fix getting option value from configuration
added TransactionTrait, fixes nested transactions
Merge pull request #577 from gharlan/transaction-trait

added TransactionTrait, fixes nested transactions
use transaction()
Merge pull request #578 from gharlan/transaction-internal-usage

internal usage of transaction()
added missing return statement
Merge pull request #580 from gharlan/missing-return-statement

added missing return statement
Added parallel migrations (without tests)

Fixed missing method
Added MigrationManager tests and fixed a bug in MigrationManager
Fix for Only variables should be passed by reference
Fixed migrationTableExists on sqlite