Some bug fixes for the CSV export.

- Checks and creates the folder in data for the csv exports if there isn’t one.
- The exports are now put in environment dependant folders; so for instance any exports ran on development mode won’t be served in production mode.
- Dropped the exception handling
Cronolog and rotate log parameters are back to biocat_local.
Cronolog and rotate log parameters split between biocat_local and environments.production.rb. Yet again.
Yet anothr tweak of rotate logs params.
Yet anothr tweak of rotate logs params.
Yet another tweak of rotate logs params. Again.
Added config/environments/production.rb.pre and ignoring config/environments/production.rb which now has to be configured for each Catalogue installation.
Fixed missing directory error.

In the Curation View, we check to see if there are any recent CSV exports before displaying the link to download them. If the directory doesn’t exist then it throws an error, so we  might as well create the directory if it doesn’t exist
Removed the option for curators to generate a new CSV export.

As the BioCatalogue takes such a long time to generate the CSV export we have removed the option for curators to do so and instead allow curators only to download a pre-generated one.
There is now a download page that tells them when the last export was generated and how to request a new export be generated if it is not recent enough.
Moved all of the csv export logic from the curation_controller to the curation_helper so that it can be used by a rake task
Stops it from breaking if certain methods return nil
Fixed bug that would crash the generate_stats script. See comment for explanation
Rake task to generate a fresh CSV Export zip.
Fixed registry stats page

As the production stats were so large, using the cache to store the results was becoming problematic. I’ve now got the stats saved in yaml format in the data folder which can be read in by the controller when the page is opened
Updated the .gitignore to reflect the recent change to making the yaml file care about the environment
Sorted out bug where the stats page broke because some previous search queries were using utf-8.
Added installation instructions link to README.
Merge branch 'master' of github.com:myGrid/biocatalogue
Check if services' CSV export is null before calling any opertions on it. A small rewording of the text on the page as well.
Changed the stats page not to refresh ever 60 seconds and fire up a background job to generate stats.