added database type to settings.txt

Signed-off-by: Prashant P Shah <pshah.mumbai@gmail.com>
fixed PHP errors when empty amount in ledger creation

Signed-off-by: Prashant P Shah <pshah.mumbai@gmail.com>
Switched license to Apache License, Version 2.0

Signed-off-by: Prashant P Shah <pshah.mumbai@gmail.com>
Released webzash v1.7

Signed-off-by: Prashant P Shah <pshah.mumbai@gmail.com>