New `Transactions` class derived from `list` to add auxilliary methods to a
transaction list.
New get_transactions_by_(year,month,category) methods return dict sorted
by (year,month,category).
Also adds sort_by_bank inplace.
reader.py is removed, with main.py becoming the main function where all
others are called from.
All categories added on categories.py, each with its own search function
and regex. The categorize function is also defined on the base class
The parsers have been cleaned to a more strimmed version. Each parser has
its own parse method and encoding and separator attributes.
The `Transaction` class has been incremented with all the comparator
methods. It also has the read and write from file methods.
The transactions.pickle is no longer used, since changes can be done
directly to the parsed data in the data_dir, making the file unused. A
manual categorization function has been created to help fill in the
gaps, interchangeable with directly editing the parsed .csv files. The
master record of data are the .csv present in the data_dir.
