Initial commit - support for finish without CFG support
Initial support for clauses: parses and build AST nodes for accum, in, out, inout, await, phased. Do not support CFG, still some warnings about unused variables when a clause has more than one argument, no checks on the kind of expression the clauses contains.
Add HcConstruct abstract class, from which finish, async, isolated can derive. This doesn't really help very much to factorize code because some visitors cannot work with abstract classes and ASTNode creation would require to trickle done some sort of authentication, such as a kind or a Class
Add support for async parsing and AST nodes.
Disable unused-value warning when parsing hc clauses, because we don't care if an expr result for a clause argument is not used
Fix the default case in getKindAsString