Methods to not cause exception on misses.

[mmicco-godaddy]

I wanted to have the ability when using database to NOT throw an AddressNotFound exception. In this pull request I implemented this in the following way:

1. I only made the change for the DatabaseReader. I am assuming the cost of the exception is less important if calling webservices, as they would have more overhead to begin with.
2. Instead of implementing a change to the existing methods that do a get, I made two new methods for city and country named "TryGet" that follow .NET's standard TryGet methodology.
3. If these changes are acceptable, I will also implement TryGet's for the ISP, connection type and domain lookups before a final pull request.

Additional question: is there any versioning or assembly info changes I need to make for a pull or will that just be taken care of by the next release? (given my pull is accepted)

[oschwald]

I apologize for not responding to your question in #11 previously. Our databases should have records for almost all public, allocated IP addresses. As such, I am not sure I understand the use case where exception handling is a significant burden. Generally, if you are getting a significant number of exceptions, that suggests that there is an integration problem, such as using the private IP of load balancer rather than the public IP of the end user.

[mmicco-godaddy]

Cool. I admit I did not do any comprehensive test to see what the miss % would be even if I ignored any internal ip addresses. I probably will measure that during some performance testing.