Basic support for dynamic fields
Able to speficy dependencies for fields
Fixed unability to append rows to an empty manager
Updated example.py
Added field decorator for simpler definition of dynamic fields
Simplified the code of field decorator using inspect module
Respect column names of dynamic fields
Evaluate dynamic fields in the correct order
filter to handle dynamic fields
Removed todo
Updated example and readme
Added imports to readme
Optimized reading
Merge pull request #2 from kdani3/dynamic_fields

Dynamic fields