data_formats is not available yet

[Greg Couch]

When I start ChimeraX with the latest source code, I get:

NOTE: Traceback (most recent call last):
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\runpy.py",
line 194, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\runpy.py",
line 87, in _run_code
    exec(code, run_globals)
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\ChimeraX_main.py", line 915, in <module>
    exit_code = init(sys.argv)
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\ChimeraX_main.py", line 624, in init
    sess.ui.build()
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\chimerax\ui\gui.py", line 196, in build
    self.main_window = mw = MainWindow(self, self.session)
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\chimerax\ui\gui.py", line 444, in __init__
    fh = FileHistory(session, self.rapid_access, bg_color=ra_bg_color,
thumbnail_size=(128,128),
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\chimerax\ui\file_history.py", line 34, in __init__
    self.update_html()
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\chimerax\ui\file_history.py", line 86, in update_html
    html = self.history_html()
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\chimerax\ui\file_history.py", line 41, in history_html
    files = file_history(self.session).files
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\chimerax\core\filehistory.py", line 216, in file_history
    session.file_history = fh = FileHistory(session)
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\chimerax\core\filehistory.py", line 32, in __init__
    self._files = self.load_history() # Map (file path, database) to FileSpec
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\chimerax\core\filehistory.py", line 123, in load_history
    fs = FileSpec.from_state(self.session, f)
  File "A:\cygwin64\home\gregc\src\chimerax\ChimeraX.app\bin\lib\site-
packages\chimerax\core\filehistory.py", line 199, in from_state
    format = session.data_formats[format].nicknames[0]
AttributeError: 'Session' object has no attribute 'data_formats'

[Greg Couch]

Rebuilding everything from scratch fixed it. Unclear why partial rebuilds failed.