Update README.md

Modified conventions configuration documentation according to updated API with `AddConvention<TConvention>` method.
Namespaces should match exactly in stead of just containing the string when scanning the assembly.
Merge branch 'master' of https://github.com/HenkMollema/Dapper-FluentMap.git
Fixed tabs in README.md
Merge pull request #7 from HenkMollema/master

Merge branch 'master' into 'transformations'