Helper function that searches for CSS property value range next to
iterator's current position
@param {TokenIterator} it
@returns {Range}
function findValueRange(it) {
		// find value start position
		var skipTokens = ['white', 'line', ':'];
		var tokens = [], token, start, end;
		
		it.nextUntil(function(tok) {
			return !_.include(skipTokens, this.itemNext().type);
		});
		
		start = it.current().end;
		// consume value
		while (token = it.next()) {
			if (token.type == '}' || token.type == ';') {
				// found value end
				trimWhitespaceTokens(tokens, WHITESPACE_REMOVE_FROM_START 
						| (token.type == '}' ? WHITESPACE_REMOVE_FROM_END : 0));
				
				if (tokens.length) {
					start = tokens[0].start;
					end = _.last(tokens).end;
				} else {
					end = start;
				}
				
				return range(start, end - start);
			}
			
			tokens.push(token);
		}
		
		// reached the end of tokens list
		if (tokens.length) {
			return range(tokens[0].start, _.last(tokens).end - tokens[0].start);
		}
	}