README/pom: Update project page & source hosting.

ExpressionBuilder: Move evaluation loop to operator objects.

Literal: Remove.

It was a no-op base class.

Type: Extend from Expression, compare with is().

ExpressionBuilderTest: Add test for index associativity.

ExpressionBuilder: Correct group open associativity.

If there are two groups ((a)), the inner group comes first.
Though in practice this doesn’t matter because groups are enclosing.

ExpressionBuilder: Let operators decide how many operands to push back.

ExpressionBuilder: Add tokens names to operators for better error output.

Scope/InstructionObject: Change address and resolve type to expression.

Expression: Remove resolve(), only have it on Passthrough (abstract).

Sequence: Support indexing into strings.

Expression: Rename getList() to getFlatList().

Because it flattens deeply nested sequences.

Sequence: Support nested and indirect lists for db / dw / dd.

Adds a sequence type for matching. Not used it in Expression getHead / getTail
yet because those are used in parameter matching where it doesn’t work yet.

Expression: Rename getElement / getNext to getHead / getTail.

Match the methods on Sequence.

IntegerLiteral: Provide “of” factory method rather than new-ing everywhere.

Including an overload for booleans.

expressions: Replace get*-methods with a get(type) method.

This cleans up the code a lot and allows us to more easily reason over types.

Annotation: Add to pass-through expressions and add proper is-checks.

Also make the default implementations not return null and this.

expressions: Replace is*-methods with an is(type) method.

This cleans up the code a lot and allows us to more easily reason over types.

Instruction: Make context mandatory.

Identifier: Remove exists check for isRegister, isFlag and isGroup.

No longer needed since Context.getSymbol returns the bottom type now which
evaluates true for every type, rather than throwing an exception.