Merge branch 'master' of git@github.com:wycats/merb-core

* 'master' of git@github.com:wycats/merb-core:
  make the default rake task 'specs' so running rake in merb-core just runs the 
  specs
  Rename @status to @_status
  Avoid adding nil values in place of missing keys for Hash#only
  Fix issue with null segments
  Fixed session cookie expires value [#366 state:resolved]
  Made HTTP method override proc-based and pluggable. [#364]