Merge pull request #15 from Aplopio/fix/posthandler-queue

Refactor code and and change in `post_handler` queue.
Setting input file flag to false on failures
Removing redundant returns of input_files_objects
Merge pull request #16 from Aplopio/cleanup

Setting input file flag to false on failures
setting flag to false if conversion fails
Merge pull request #17 from Aplopio/cleanup

setting flag to false if conversion fails
Merge pull request #18 from Aplopio/fix/posthandler-queue

Add supervisor conf for post hadnler queue
Fixing syntax errors
Merge pull request #19 from Aplopio/cleanup

Fixing syntax errors
Merge pull request #20 from Aplopio/fix/posthandler-queue

Remove extra call to post handler.
Fixing bug in conversion
Merge pull request #21 from Aplopio/bug_fix

Fixing bug in conversion
Merge pull request #22 from Aplopio/fix/posthandler-queue

Change working of post handler when conversion fails.
Merge pull request #23 from Aplopio/fix/posthandler-queue

Change in handler completion function parameters.
Merge pull request #24 from Aplopio/fix/posthandler-queue

Add catch for OSError exception
Fix in HTML to PDF converter.