Added script to create connections URIs

I added a module to compose a postgreSQL connection URI string from a parameters
object
Implemented test, fixed issues and added feature

I created the test to test connection-string and fixed the issues, and I
added the feature to the module and changed the module test according
the new feature that allows to provide an object with the connection
parameter rather than a connection string
Added compatibility with the previous release

As commented, I added the compatibility with the previous release, which
received a connection string under a options' property. I also restored
the test for checking this fix
Merge pull request #1 from ifraixedes/master

Added connection-string builder