Add SpanScanner.location.

pkg/string_scanner/CHANGELOG.md

+## 0.1.1
+
+* Declare `SpanScanner`'s exposed `SourceSpan`s and `SourceLocation`s to be
+  `FileSpan`s and `FileLocation`s. They always were underneath, but callers may
+  now rely on it.
+
+* Add `SpanScanner.location`, which returns the scanner's current
+  `SourceLocation`.
+
 ## 0.1.0
 
 * Switch from `source_maps`' `Span` class to `source_span`'s `SourceSpan` class.
 
 * `new StringScanner()`'s `sourceUrl` parameter is now named to make it clear
   that it can be safely `null`.
 
 * `new StringScannerException()` takes different arguments in a different order
   to match `SpanFormatException`.
 
@@ skipping 19 matching lines @@
   access to information about the errors that were thrown and can provide
   terminal-colored messages.
 
 * Add a `LineScanner` subclass of `StringScanner` that automatically tracks line
   and column information of the text being scanned.
 
 * Add a `SpanScanner` subclass of `LineScanner` that exposes matched ranges as
   [source map][] `Span` objects.
 
 [source_map]: http://pub.dartlang.org/packages/source_maps