+ Iseq module for pretty printing
+ Syntax constants
+ Syntax unary primitives
+ Syntax binary primitives
+ Syntax patterns
+ Syntax expressions
+ Syntax main module
! pprAExpr instead of pprExpr in tuple

To get parantheses
+ Syntax for types
Merge branch 'feature/syntax' into develop
+ Changelog update
+ Renamed Pval to Pvar
+ Substitution on types
- Removed restrictions on Expr export
+ Errors module
+ Counter for generating type vars
+ Type constraints
+ Unification
+ Typing environment
+ Typing of constants