fixed deletion of post with attachment
Enhanced file uploader

- added debug log for various functions of the csv & pdf uploader
- remove csv file after a successful class import
- added a filter for the uploaders to prevent files of other types
being added to the queue - eg. pdf - ques & answer, csv - class import
Simplified the generation of number of judgements left

Previously, number of judgements left were generated by looping
through all the judgements returned by the API and comparing the
count with the required number. Now, I have moved the count to the
API, by modifiying the query for the judgements. With the change,
the API does one fewer marshal.

I have also moved the total_comments_count from PostsForQuestions,
which is no longer used.
Added instructions to tempoarily solve Issue #79