Changed signature of conditions to narrow parameter down to getter
Implemented validation for Block
new validation checks & validation for base entities and block

Also implemented test for block validation
Implemented validation and validation tests for DataArray
Implemented validation and validation tests for DataTag
Validation for dimensions, new checks and further check in base entity

Implemented validation for all dimension types, added new checks like ```isGreater``` and extended validation of the base entity
Implemented validation & test for Feature, corrected checks
Implemented validation & tests for File
Implemented validation & tests for Property
Implemented validation & tests for Section
Minor renaming of validation test methods
Implemented validation & tests for SimpleTag
Implemented validation & tests for Source
Fixed entities not calling base entity validation
Fixed call to property base validation
Merge pull request #270 from balint42/validation

Validation

LGTM