Allow nested Raw queries

* Do the recursive step on constructor
* Splice in parameter strings based on ? indexes
* Concat bindings
Only nest raws when the sql is a string
transactions
create if not exists
bugfix: index disruption
fix transactions
Unit test for nested raws
fix for using a pgConnectionString, the parsed connection string settings will be set in the connectionSettings of the knex object.   Without this, some features like columnInfo() will fail when connecting to a database with a pgConnectionString
chainable-first method for MySQL
Added oracle support
Reverted mysql overlapping join test
oracle - added support for multiple returning values
oracle - added seeder
Fix #422, transactions & Bluebird 2.3
Merge pull request #383 from calvinmetcalf/create-if-not

Create if not
Merge pull request #419 from vschoettke/oracle-support

Add Oracle support
Merge pull request #390 from bhirt-bpl/master

fix for using a pgConnectionString
Merge pull request #379 from SohumB/feature/nested-raw

Allow nested Raw queries
Merge pull request #406 from hsz/chainable-first

chainable-first method for MySQL