Removed marked package, added mrt support, installed marked smart package
Extension support.  Meteorite, extensions+marked smart packages.

1) Started using Meteorite (run with 'mrt' instead of 'meteor')

2) To enable markdown renders on the client, the marked smart
   package was installed.  Consequently, the marked node package
   was removed, and the showdown package removed, but all these
   functionalities are provided by the smart package.

3) "Extensions" smart package installed.

4) 5 hooks added into the Meteorpedia codebase.
extensions version bump
meteor-extensions version bump
removed duplicate code
Merge pull request #4 from gadicohen/extensions

Extension support. Thanks so much gadi, looks great. :)