add solr search engine (partly fixes issue#35)

This commit adds solr search engine and indexes projects and users so
that we will be able to implement a search in the next commit.

In order to start solr engine, you need to run:

rake sunspot:solr:start

and then run

rake sunspot:reindex

for indexing the models in the database

Then, you can check it works entering into a rails console and typing:

> result = Project.search do
>     keywords "test"
>   end
> result.results

Assuming you have a project with the keyword "test" in either the title
or the description, you should get this/these project/s as a result.
add sunspot solr deploy tasks to mina

I've based this changes on the webistrano recipe that we have for other
projects.

I am adding start, stop, restart and reindex and I am forcing restart on
each deployment because deployment means changing directories and I
think that is the reason we need to restart sunspot.

Reindexing is only needed if you change the models or the searchable
blocks in the models and it is a very expensive operation, thus we
should not run it on every deploy.
fix indentation in config/routes.rb
add controller for projects/search
add user/search controller
set sunspot solr to start before running the tests (and stop after)
Merge pull request #43 from jordimassaguerpla/master

add solr search engine (partly fixes issue#35)