Dev/constructors

[kasra-keshavarz]

A few quick fixes and improvements:

• Adding three new constructors to initiate and Easymore instance using dictionaries, JSON strings, and JSON file paths,
• Making __init__ function more pythonic,
• Making Easymore the main importable class of the easymore package,
• Making __version__ variable reading from the package itself rather than redefining in the main script,
• Adding dict constructor could possibly help with a CLI, and
• Throwing Exceptions at the user instead of sys.exit function.