bypass/minimize file system caching for a program

 `nocache` tries to minimize the effect an application has on the Linux
 file system cache.
 .
 Use case: backup processes that should not interfere with the present
 state of the cache.
 .
 Also this package provides the following utilities:
 * `cachedel` : clear page cache for a file.
 * `cachestats` : print number of cached vs. not-cached pages for a file