Replaced class methods by factory methods.

Non-dotted classes should be removed from the parser.
Fixes bug #58, but breaks shadowing logic.

Bug #58 was caused by re-writing parameter declarations into
memberNodes.  This is fixed here, but the no-shadowing logic is
broken in this commit.

Various parser error-mesages are also improved, incuding #60.
Merge branch 'dupDecls' of https://github.com/apblack/minigrace into dupDecls

I've no idea what git is doing in this merge.
Merge branch 'dupDecls'

of https://github.com/apblack/minigrace into dupDecls.
I've no idea what git is doing in this merge.
There seem to be no changes and no additions, but git insists
that I'm behind the origin repository.
Merge branch 'dupDecls' of https://github.com/apblack/minigrace into dupDecls
Changes the shadowing logic to permit methods.

Here methods includes defs, vars and imports in objects,
since these define methods.
This version doesn't yet work correctly for top-level vars;
specifically, it objects to 'isStandardPrelude' in collectionsPrelude,
presumably because it is already defined (as a method) in
StandardPrelude.
Corrects line numbers for symbol table.

Symbols are now added to scope with the correct line
numbers more often, so the duplicate detection logic
now works correctly.

However, inheritance does not work correctly in this version;
collectionPrelude, which has multiple instances of inheriting
from a trait method, breaks it, for example.
Experiments with getScope.

Changes printing of ast for clarity.
Parser rejects blocks in inherits statement, simplifies error message.
Scopes are classified by variety from birth.
Adds objectdraw.grace to .gitignore

That’s all!