Fix #33

* Parse: Add conid to simple patterns
* AST: Add ConidPattern Node
* Parse Test: Enable relevant test
Merge remote-tracking branch 'dionyziz/master' into fix_33
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.
Merge branch 'master' into fix_33

Conflicts:
	compiler/parse.py
Conflicts were a result of simplification of pattern rules in the
upstream branch
Fix simple pattern test in order to be up to the current standards
Fix bad merge conflict resolution.
Merge pull request #59 from dimkou/fix_33

Enable conid as simple pattern
AST, Parse, Parse test: Separate constants from functions.

* Add ConstantDef node.
* Parse parametre-less function definitions as constants
* Require param_list to be non-empty (i.e. param_seq)
* Adapt parsing unit tests accordingly.