#133 - rough implementation of improved scanning for extensions, inspired by Nancy
#133 - removing commented-out code
implemented Adam Ralph's comments from initial commit
extra tests for found/not found extensions
implemented test for loading extension types from non-AppDomain assembly
tidying
removing Designer from packages.config
restoring BOM
Merge pull request #135 from blairconrad/issue133

Issue133
#133 reformatting and refactoring of ApplicationDirectoryAssembliesTypeCatalogue
* moved field assignment from constructor to initializer
* inlined single use private methods
* inlined variables
* shortened variable names
* replaced foreach continuation with Linq method call
* reduced nesting
* formatted comments
* whitespace
Merge pull request #136 from adamralph/133

#133 minor reformatting and refactoring of ApplicationDirectoryAssembliesTypeCatalogue