Make hotkey preference work

Separate preference handling into a new class and have the previous
preferences class handle only the preferences window.

We rename the old file to `preferences_window.py` and adjust the
`info.plist` key for the menu item accordingly.

Our new `Preference` class can now be imported from both
`equalize_sidebearings.py` and `preferences_window.py` without causing
confusion. I extracted it because asking for the
`DEFAULT_ACTIVATION_KEY` from `preferences_window.py` from
`equalize_sidebearings.py` would open the preferences window (bad).

We now save the preferred key using RoboFont's extension preferences
API.

When the text input in the preferences window is modified, the new key
preference gets saved.

BUG:
There's an issue with this implementation where the preferred key
doesn't become active until the next launch of RoboFont because
`EqualizeSidebearings` has its own instance of `Preferences` which has a
stale `activation_key`.

1 files changed, 4 insertions, 2 deletions

diff --git a/equalize_sidebearings.py b/equalize_sidebearings.py
index 18515ad..5660330 100644
--- a/equalize_sidebearings.py
+++ b/equalize_sidebearings.py
@@ -1,6 +1,8 @@
 from mojo.events import addObserver
 from lib.doodleMenus import SpaceCenterMenuForGlyph
 
+from preferences import Preferences
+
 
 class CustomSpaceCenterMenuForGlyph(SpaceCenterMenuForGlyph):
 
@@ -10,13 +12,13 @@ class CustomSpaceCenterMenuForGlyph(SpaceCenterMenuForGlyph):
 
 
 class EqualizeSidebearings(object):
-    DEFAULT_ACTIVATION_KEY = 'e'
 
     def __init__(self):
         addObserver(self, 'equalize', 'spaceCenterKeyUp')
+        self.preferences = Preferences()
 
     def equalize(self, info):
-        if info['event'].characters() == self.DEFAULT_ACTIVATION_KEY:
+        if info['event'].characters() == self.preferences.activation_key:
             space_center_menu = CustomSpaceCenterMenuForGlyph(
                 info['glyph'].naked())
             space_center_menu.equalSideBearings_(self)