Initial commit in  project

Added Core reference
Merge branch 'develop' of https://github.com/renehernandez/InfoRecovery into feature/boolean_model
Merge branch 'develop' of https://github.com/renehernandez/InfoRecovery into feature/boolean_model
Merge branch 'develop' of https://github.com/renehernandez/InfoRecovery into feature/boolean_model
Ignore grammar files
Adding grammar files
Adding boolean query AST and AST adapter
Merge branch 'develop' of https://github.com/renehernandez/InfoRecovery into feature/boolean_model