updates to make javascript actually behave correctly for real.

updates to make javascript actually behave correctly for real.
Autodetection is fixed, load of JS dependent items (like address book and
search) will be set to false if javascript_on session var is false/0.

javascript_on will ONLY be true if:
  javascript_setting = 1 (ALWAYS)
  javascript_setting = 2 (Autodetect, and test works)

If you change your javascript settings, javascript_on will change
immediately.

We might actually want to DISABLE Always, and have it be either Never, or autodetect.
Since Always might not always work.. :-P

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@6918 7612ce4b-ef26-0410-bec9-ea0150e637f0