Do not reload core.keymap module

Avoid reloading the core.keymap module when user's config
or project module change.

The reason is the plugins like autocomplete can add keymaps
and the additions from plugins would be lost.

Close issue #793

data/core/init.lua

@@ -82,7 +82,6 @@ end
 
 local function reload_customizations()
   core.reload_module("core.style")
-  core.reload_module("core.keymap")
   local plugins_save = {}
   for k, v in pairs(config.plugins) do
     plugins_save[k] = v