rename runtimectl to document/canvascontext

frontend/device/android/device.lua

@@ -27,6 +27,18 @@ local Device = Generic:new{
     hasClipboard = yes,
     hasColorScreen = yes,
     hasOTAUpdates = canUpdateApk,
+    --[[
+    Disable jit on some modules on android to make koreader on Android more stable.
+
+    The strategy here is that we only use precious mcode memory (jitting)
+    on deep loops like the several blitting methods in blitbuffer.lua and
+    the pixel-copying methods in mupdf.lua. So that a small amount of mcode
+    memory (64KB) allocated when koreader is launched in the android.lua
+    is enough for the program and it won't need to jit other parts of lua
+    code and thus won't allocate mcode memory any more which by our
+    observation will be harder and harder as we run koreader.
+    ]]--
+    should_restrict_JIT = true,
 }
 
 function Device:init()