Merge pull request #1 from DavoudTaghawiNejad/master

pull request, after merging for the first time
MySQL DB connection

Added a class DB connection to handle database connection, currently the
class store all worker's parameters in the daabase..
SQLitte addition

now the ABM stores firms daily data and aggrigate results into SQLite
database
DBConnection cleanups

naming, comments, cleaning
SQLite Parameters

Setup parameters, style changes, correction in values entered into
database (Some values are divided by firm size to calculate averages.
Remove MySQL + code style

Removed all methods for MySQL database connection, since SQLite is by
far, faster and don't need prior setup...

Style corrections
database connection Abdulaziz (with changes by me)