Generate strongly named assemblies by default

[jariq]

As I currently see it there are three options when it comes to strong naming open source library:

OPTION 1: Generate single unsigned assembly/package:

• works in projects that do not require strong naming
• works in projects that require strong naming
• easy to maintain

OPTION 2: Generate single signed assembly/package:

• works in projects that do not require strong naming
• works in projects that require strong naming
• easy to maintain (with .snk publicly available in the repository)

OPTION 3: Generate two separate assemblies/packages, one signed and one unsigned:

• works in projects that do not require strong naming
• works in projects that require strong naming
• easy to maintain (doubles the work and may cause issues in projects with complex dependencies)

Historically Pkcs11Interop up to the version 3.3.0 was using OPTION 1 but then in #41 I decided to switch to OPTION 3 because I considered that option to be the least harmful for existing users in that time. Now that we are approaching next major release I am going to switch to OPTION 2 on all platforms that support strong naming.