Better organisation

The library is meant to be a very simple parser, it must stick to its role.

Following actions where made:

• Removed all features related to parsed data manipulation (except the ability to provide defaults values when using helpers functions).
• Added the ability to parse strings in addition to files.
• Refactored Parser class to keep only parsing related features.
• Moved helpers to static functions into a dedicated Helpers class.

Added the "get" method

v1.0.1

Implement get method

v1.0.0

Improve documentation