Added the ability to login wihtout security token where the ip filtering
authentication method is in use. Created a new constructor for
SalesforceLogin which takes the following params username, password,
organizationId, sandbox=False,sf_version='23.0' and uses slightly
different login soap request.
Added descriptions for the new Salesforce authentication method of IP
Filtering
Fixed a bug where SalesforceLogin was overwritten by a method with the same name and refactored both functions into a
single one to support both IP Filtering and Security Token authentications methods
Merge pull request #11 from davideagle/master

Added the ability to login wihtout security token