TrigFTKSim: Fix clang and other warnings.

clang warnings:

• Don't use std::move on rvalues.
• Unused variables.

Don't put using directives in header files.

Remove from cmake file reference to non-existent file.

Fix placement of restrict keyword (was causing clang compilation to fail). Use ATH_RESTRICT macro for this non-standard language feature.

User-defined identifiers should never use two underscores in a row, or start with an underscore followed by an uppercase letter.