Log Message:
Update to 1.28. From the changelog:

General
* Improve support for GTK 3.20.
* System filetype files and system tags files are now in sub-directories
  *filedefs/* and *tags/* respectively (Jiří Techet, PR#485).
* Remove Waf build system (PR#769).

Interface
* Allow to set a keybinding for File->Properties (Issue#622, PR#952).
* Make it possible to define default symbol_list_sort_mode (Jiří Techet,
  Issue#313, PR#581).
* Add keybindings for custom commands 4 through 9 (Thomas Sahlin, PR#858).
* Use "Symbol" in place of "Tag" everywhere it does not \ 
refer to markup
  tags (Jiří Techet, Issue#579, PR#582).

Bug fixes
* Fix canceling keybinding overriding by discarding the dialog (Issue#714).
* Fix type name coloring when types change (Jiří Techet, PR#1039,
  Issue#1020, Issue#1022).
* Fix undo of line end type change (Jiří Techet, PR#527, Issue#409).
* Fix build with GLib < 2.32 (Issue#764).
* Fix missing progress bar during build runs (Issue#765).
* Fix infinite loop when performing reflow on some input with many
  consecutive spaces (Issue#848, PR#852).
* Fix some locale encoding conversion issues (Jiří Techet, PR#547).

Editor
* Update Scintilla to version 3.6.6.
* Improve Goto Symbol popup contents (Jiří Techet, PR#958).
* Update Scintilla to version 3.6.3 (including improved support for Lua
  5.3 and Perl 5.22).
* Greatly improve scope completion (Jiří Techet, PR#488, PR#505, PR#862,
  PR#906).
* Performance improvement highlighting types (Jiří Techet, PR#575).
* Show calltips after a C++ explicit specialization (PR#496).
* Show a popup to select the symbol when going to a symbol has several
  options (Jiří Techet, PR#406, PR#923).

Filetypes
* Treat `.h` headers as C++ by default (Jiří Techet, PR#857).
* Various improvements to the Ruby parser (Issue#587).
* Fix Haskell single line comments (Alexander, PR#1029).
* Update Java keywords (Yan Pashkovsky, PR#1024).
* Fix handling of curly brackets in Make (Masatake Yamato).
* Add ECMAScript 6 keywords (Chris Mayo, PR#980).
* Slight improvement to the Java file template (Philipp Wiesemann, PR#1073).
* Add missing `last-child` CSS pseudo-class (Issue#1102).
* Added some extra Markdown extensions (Andrea Stacchiotti, PR#820).
* Add `.asm51` and `.a51` extensions for 8051 assembly (Devyn Collier
  Johnson, PR#739).
* Fix C++ namespaces scope (Issue#871).
* Fix parsing of C++ global scope qualifiers in base class lists.
* Use the C++ parser for CUDA filetype (Issue#830, PR#831).
* Add Clojure file extensions (Daniel Șuteu, PR#842).
* Improve return type and var type recognition in C, C++, C# and D
  (Issue#845, PR#889).
* Fix parsing of C++11 raw string literals (PR#879).
* Update built-in PHP symbols (Issue#584, PR#603).
* Fix parsing some Objective-C properties (PR#940, PR#941).

Internationalization
* Updated translations: ca, de, el, es, fr, it, ja, lt, pt, ru, sk,
                        tr, zh_CN
* Updated translations: de, es, fr, it, ja, kk, lt, nl, pt, ru, sk,
                        zh_CN

API
* Don't require static strings for key group name and label (PR#1126).
* Formally add TMTag to the API (Thomas Martitz, PR#1093).
* Add `editor_set_indent_width()` (Thomas Martitz, PR#903).
* Add `GeanyFiletypeID` and deprecate `filetype_id` (PR#932).
* Remove non-API type `langType` (Jiří Techet, part of PR#906).
* Mark deprecated API so GCC-like compilers can warn about it, and add
  `GEANY_DISABLE_DEPRECATION_WARNINGS` to silence those (PR#911).
* Add `scintilla_object_send_message()`, `scintilla_object_get_type()`
  and `scintilla_object_new()` alias to the API as synonyms for their
  legacy counterparts `scintilla_send_message()`, `scintilla_get_type()`
  and `scintilla_new()` (Thomas Martitz, PR#874).

Plugins
* Class builder: use `.hpp` extension for C++ headers by default
  (Yan Pashkovsky, PR#999).

Windows
* Show an error if an URI cannot be opened (PR#1079).
* Project->Open now respects the native dialog setting (PR#961).

OSX
* Fix refreshing the keybindings displayed in the menus (Jiří Techet,
  PR#973).