Parse, AST: Allow Pattern without arguments; deprecate ConidPattern.
Solve reduce/reduce conflict in patterns.

* Parse: Replace simple_pattern_list with simple_pattern_seq.
* Parse test: Fix and expand testing of simple_pattern_seq.
Parse: Split pattern rule for clarity.
AST: Drop deprecated ConidPattern node.
Merge pull request #2 from Renelvon/fix_33

Solve reduce/reduce conflict in patterns.