Rework module system

Don't require/allow naming a module, instead require that the importer
names it. Allow importing into the local scope with the name !Local.
Simplify namespacing logic. Updates all tests to reflect these changes.

src/Research.hs

@@ -26,7 +26,6 @@ data TricuAST
   | TFork TricuAST TricuAST
   | SLambda [String] TricuAST
   | SEmpty
-  | SModule String
   | SImport String String
   deriving (Show, Eq, Ord)
 
@@ -34,17 +33,18 @@ data TricuAST
 data LToken
   = LKeywordT
   | LIdentifier String
+  | LNamespace String
   | LIntegerLiteral Int
   | LStringLiteral String
   | LAssign
   | LColon
+  | LDot
   | LBackslash
   | LOpenParen
   | LCloseParen
   | LOpenBracket
   | LCloseBracket
   | LNewline
-  | LModule String
   | LImport String String
   deriving (Show, Eq, Ord)