Remove backstage redundancy in TiddlyWiki

These changes get rid of the redundant iframes that contain
_space and _account from the tiddlywiki backstage, and replace
the tiddlyspace circle thing in the middle with standard
backstage as dropdowns.

This is done for several different reasons:

* Get rid of redundancy
* Make way for the tiddlyspace bar (which will ride above
  the tiddlywik bar, presumably)
* Fix issues with behaviors in the backstage when logged in,
  not logged in or unplugged.
* Begin a process of making tiddlywiki more lightweight.

Still to do:

* move some code to TiddlySpaceConfig
* update tests

A lot of code which is now apparently dead has been removed,
including quite a bit of CSS.

src/backstage/Backstage.tid

@@ -1,10 +1,7 @@
-modifier: osmosoft
-tags: excludeLists excludeSearch excludeMissing
-
 !SpaceUnplugged
 {{unpluggedSpaceTab{
 {{wizard{
-<<image unsyncedIcon width:48>> <<message messages.syncExplanation>>
+<<image unsyncedIcon width:48>> If you are unplugged, from here you can sync your offline version with the online version.
 }}}
 {{wizard syncKey{
 {{keyHeading{
@@ -17,23 +14,16 @@ Key}}}
 <<message messages.memberStatus>> <<homeLink>>
 {{unsyncedList{<<message messages.syncListHeading>> <<list filter [is[unsynced]]>>}}}
 
-<<tabs txtTiddlySpaceTab
-search "search across TiddlySpace" Backstage##Search
-tiddlers "tiddlers control panel" Backstage##BackstageTiddlers
-plugins "Manage installed plugins" PluginManager
-batch "Perform batch operations on public/private tiddlers" Backstage##BatchOps
-tweaks "Tweak the appearance and behaviour of TiddlyWiki" AdvancedOptions
-"import/export" "Import/export tiddlers from/to a TiddlyWiki" Backstage##ImportExport
->>
 running TiddlySpace@glossary version <<message extensions.tiddlyweb.status.tiddlyspace_version>>
 {{autotable{
 <<tiddler Backstage##Resources>>
 }}}
 
 !Resources
-[[blog|@@blog]] [[documentation|@@docs]] [[featured spaces|@@featured]]
+[[blog|@@blog]] [[documentation|@@docs]] [[featured spaces|@@featured]] 
 
 !Search
+Search across the entire TiddlySpace service.
 <<tsSearch>>
 
 !ImportExport
@@ -73,3 +63,13 @@ You can download this TiddlySpace as an offline TiddlyWiki:
 
 !BatchPublic
 <<TiddlySpacePublisher type:public>>
+
+!Plugins
+''Note:'' Many of these plugins are core TiddlySpace plugins and cannot be changed unless first cloned.
+
+<<tiddler PluginManager>>
+
+!Tweaks
+These options change behavior in TiddlyWiki //only// and may be ineffective in TiddlySpace.
+
+<<tiddler AdvancedOptions>>