Location of ROS specific annotations

[TomyYamy]

This relates #97.
We are supporting ROS.

publish_var : String - variable name to be published
publish_var_field : String - variable field to be published

It is in spec layer.

[TomyYamy]

@nickovic
Still I feel we may remains it in spec. rather than AST or semantics.

[TomyYamy]

I find at least, AbstractParserVisitor does not support it. It is good.

[TomyYamy]

Sorry I find somehow AST relates subscribe, publish potentially in our refactoring code.
Please see commit: 5c2e95c branch: ast-refactoring-trial
rtamt/rtamt/ast/parser/abstract_ast_paser.py
declare_var() has

self.var_topic_dict[var_name] = 'rtamt/{}'.format(var_name)

Perhaps we may move it some where.

[TomyYamy]

Perhaps we may move it rtamt4ros?

[TomyYamy]

I find ANTRL parser is handing ros topic too.

rtamt/rtamt/grammar/tl/LtlLexer.g4

Lines 81 to 82 in b1f79b9

	ROS_Topic
	: 'topic' ;

I know what we do here. I know it is difficult to transfer ROS annotation to rtamt4ros.
Maybe here is discussion point.