[gjs] Created tag 1.55.4

[Philip Chimento <pchimento src gnome org>]

The unsigned tag '1.55.4' was created.

Tagger: Philip Chimento <philip chimento gmail com>
Date: 1546930897 -0800

    Version 1.55.4
    
    - Closed bugs and merge requests:
      * Various maintenance [!258, Philip Chimento]
      * Boxed copy constructor should not be called, split Boxed into prototype and
        instance structs [#215, !260, Philip Chimento]

Changes since the last tag '1.55.3':

Cosimo Cecchi (1):
      Merge branch 'december-maintenance' into 'master'

Philip Chimento (25):
      build: Post-release version bump
      jsapi-class: Fix comment
      jsapi-class: Make parameter const-correct
      mem: Split memory counters into private header
      fundamental: Remove obsolete comments
      object: Rename ObjectPrototype::new_for_js_object()
      js: Handle errors in gjs_intern_string_to_id()
      mem: Only print counter totals if >0
      fundamental: Fix error handling in find_fundamental_constructor
      gi: Rename "proxy" to "wrapper"
      js: Factor out definition of '$gtype' property
      tests: Fix typo
      module: Add memory counters
      wrapperutils: Make native address const
      repo: Fix error handling in lookup functions
      wrapperutils: Factor out gjs_define_static_methods()
      wrapperutils: Factor out Base/Prototype/Instance scheme
      boxed: Split private struct into BoxedPrototype/BoxedInstance
      fundamental: Port private struct to wrapperutils
      gerror: Split private struct into ErrorPrototype/ErrorInstance
      interface: Split private struct into InterfacePrototype/InterfaceInstance
      union: Split private struct into UnionPrototype/UnionInstance
      gtype: Remove unused function
      Merge branch '215-refactor-gi-wrappers' into 'master'
      release: Prepare for 1.55.4