Updated site compilation to respect exact paths for files.

This fixes one part of issue #20, where the scripts/README file was ending up in root/README instead of root/scripts/README. The other problem in issue #20 is not re-createable at the current version (0.5.3DEV).

Added root input dir to view object to better handle exact paths of files to be
processed and moved during site compilation.

Optimized site view objects to cache the calculated output path so it doesn't
have to recalculate it each time it is called.