Add Melakartha Class

This class contains a list of Swaram objects. As usual, you can get, set
swarasthanam
Add Raagam class and Raagam DB

Contains a Melakartha class. Arohanam and Avarohanam contain list of
Swaram objects. Have implemented string parsing for Aro and Avaro input.
File reading and writing implemented
Add Swaram class

A class encapsulating swaram name and swarasthanam
Add texwrite - py to tex writer