Merge pull request #30 from adityaduggal/master

FIxes for Float field problem
Merge pull request #31 from adityaduggal/master

Added validations to Sales Invoice to DISALLOW SI from only SO or DN
Merge pull request #32 from adityaduggal/master

Minor changes to Centre Drill range
Merge pull request #18 from frappe-apps/master

Old Merge