Merge pull request #6 from itsjeyd/master

Merged pull request, thanks!
DRY: Put code that writes uploaded file to disk in separate decorator function
DRY: Move error handling code for zip extraction from validators to
extract_archive method
Create utility function that returns absolute path of file/folder in tmp directory
Create utility function that wraps os.path.splitext call
Remove "trendminer" prefix from imports in views.py
DRY: Put code that extracts zip archive in separate decorator function
Make upload process platform-agnostic: Use tempfile.gettempdir() to
determine tmp directory instead of hardcoding the path