Refactors parser error reporting

Signed-off-by: Ahmed H. Ismail <ahm3d.hisham@gmail.com>
Adds validations to document model

Signed-off-by: Ahmed H. Ismail <ahm3d.hisham@gmail.com>
Adds validations for Review model

Signed-off-by: Ahmed H. Ismail <ahm3d.hisham@gmail.com>
Adds validations to CreationInfo model

Signed-off-by: Ahmed H. Ismail <ahm3d.hisham@gmail.com>
Fixes bug in Lexer and free form text

Signed-off-by: Ahmed H. Ismail <ahm3d.hisham@gmail.com>