[NFR] cache exist function

[kenjikobe]

add a way to check if a key exists in the cache without get the contents of it

[kenjikobe]

something like $cache->exists("key") or $cache->has("key")

[phalcon]

This will be addressed in 0.6.0

[hdogan]

@phalcon I'm currently working on exists() method implementation. See the commit at my own fork at https://github.com/hdogan/cphalcon/commit/94e07b0d0ae60d5245908eea30f6a5563e000f61

Please let me know if my implementation needs changes. I haven't done functional test yet but it compiles clearly on OSX. I'll try to complete it by tomorrow.

Update: Code cleanup: https://github.com/hdogan/cphalcon/commit/fdfc772fe622f62cb7c9b96214d94695f0944726

[hdogan]

PR is already merged. This issue can be closed.

[phalcon]

thanks!