Warnings under scala 2.10 with -feature option enabled

There are lots of warnings when compiling against the library with -feature option enabled:
```
reflective access of structural type member method toCC should be enabled
by making the implicit value scala.language.reflectiveCalls visible.
This can be achieved by adding the import clause 'import scala.language.reflectiveCalls'
or by setting the compiler option -language:reflectiveCalls.
See the Scala docs for value scala.language.reflectiveCalls for a discussion
why the feature should be explicitly enabled.
        typedInstance <- instance.toCC[T]
```
This PR fixes such warnings by replacing implicit methods that return structural types, with implicit classes.
It also fixes some other warnings that arise when compiling the library itself.