Changes in bill format.
Merge pull request #348 from jasvir99/dirty

Changes in bill format.
Removes unwanted file.
Merge pull request #349 from jasvir99/dirty

Removes unwanted file.
Makes reference date field not required.
Merge pull request #350 from jasvir99/dirty

Makes reference date field not required.
Added Staff position model
Merge pull request #351 from JaskaranSingh/dirty

Added Staff position model