- Also add some tests for left direction

Emit filenames for error messages.

See merge request johannes.mey/relast!2

- Extended grammar to let TypeDecl and Relation have filename
- Extended error message to display and order first by filename
- Added testcase with multiple inputs having errors

- Simplified lexer, dropping lexical state String
- Added test case for this scenario (copied from MultipleFiles)

- Change imports in test MultipleFiles
- Organize imports in test InsertRelations

Mquat2

Closes #11, #6, and #5

See merge request johannes.mey/relast!1

use direct field access instead of getter to reduce unnecessary dependency creation when using incremental evaluation

check uniqueness during serialisation, fix nullpointer issues in rewrite checks, add test for node removal

Add flag `--useJastAddNames` generate names in the form of addX, removeX and setX. If omitted, relast will default to the original naming scheme addToX, removeFromX and setX.

make unresolved subtypes of abstract types abstract, use unresolved interface. rename resolver methods (for MQuAT compatibility)