3.2.0

CHANGES:

• Remove the AST without locations: now all functions build an AST with locations;
  in particular, parsing always provide located error messages.
  To ease backward-compatibility, the smart constructors still use the
  same interface, using dummy locations by default, with
  a With_locations module for users who wish to explicitly provide
  locations.
  (@gasche, #65)
• Support for "template inheritance" (partials with parameters)
  {{<foo}} {{$param1}}...{{/param1}} {{$param2}}...{{/param2}} {{/foo}
  following the widely-implemented semi-official specification
  mustache/spec#75
  (@gasche, 58)
• Partials are now supported in the mustache command-line tool (@gasche, #57)
  They are interpreted as template inclusion: "{{>foo/bar}}" will include
  "foo/bar.mustache", relative to the current working directory.
• Improve error messages (@gasche, #47, #51, #56)
  Note: the exceptions raised by Mustache have changed, this breaks
  compatibility for users that would catch and deconstruct existing
  exceptions.
• Add render_buf to render templates directly to buffers (@gasche, #48)
• When a lookup fails in the current context, lookup in parents contexts.
  This should fix errors when using "{{#foo}}" for a scalar variable
  'foo' to check that the variable exists.
  (@gasche, #49)