History token building/handling: Improve use of token parameters.

History token building/handling: Improve use of token parameters.

	* src/main/java/org/glom/web/client/place/HasSelectableTablePlace.java
	(HasSelectableTablePlace.Tokenizer): Add getTokenParams(String)
	and buildParamsToken(HashMap), for use by derived classes.
	Make the separator private because it is no longer be needed.
	* src/main/java/org/glom/web/client/place/DetailsPlace.java
	(DetailsPlace.Tokenizer.getToken): Use buildParamsToken()
	instead of manual string concatenation.
	(DetailsPlace.Tokenizer.getPlace): Use getTokenParams() instead
	of hardcoded indices and awkward splitting code.
	* src/main/java/org/glom/web/client/place/ListPlace.java
	(ListPlace.Tokenizer.getToken): Use buildParamsToken()
	instead of manual string concatenation.
	(ListPlace.Tokenizer.getPlace): Use getTokenParams() instead
	of hardcoded indices and awkward splitting code.
	This should fix bug #666420