Add some rudimentary extension related commands.

Adds :extadd, :extdelete, :extdisable, :extenable, :extensions.

vimperator/locale/en-US/gui.txt

@@ -5,6 +5,8 @@ Ex and Normal mode commands there may be times when directly accessing the GUI
 is required. There are commands for accessing the menu system, standard dialogs
 and the sidebar.
 
+section:Menus[menu]
+
 |:emenu| +
 ||:emenu {menu}||
 ________________________________________________________________________________
@@ -14,6 +16,7 @@ hierarchical path to the menu item with each submenu separated by a period.
 E.g. [c]:emenu File.Open File...[c]
 ________________________________________________________________________________
 
+section:Dialogs[dialogs]
 
 |:addo| |:addons| +
 ||:addo[ns]||
@@ -69,6 +72,49 @@ Show progress of current downloads. Open the original Firefox download dialog
 in a new tab. Here, downloads can be paused, canceled and resumed.
 ________________________________________________________________________________
 
+section:Add-ons[extensions,add-ons]
+
+|:exta| |:extadd| +
+||:exta[dd] {file}||
+________________________________________________________________________________
+Install an extension. {file} is an extension XPInstall file (*.xpi).
+________________________________________________________________________________
+
+
+|:extde| |:extdelete| +
+||:extde[lete] {extension}|| +
+||:extde[lete]!||
+________________________________________________________________________________
+Uninstall an extension. {extension} is the extension's name. When [!] is given
+all extensions are uninstalled.
+________________________________________________________________________________
+
+
+|:extd| |:extdisable| +
+||:extd[isable] {extension}|| +
+||:extd[isable]!||
+________________________________________________________________________________
+Disable an extension. {extension} is the extension's name. When [!] is given
+all extensions are disabled.
+________________________________________________________________________________
+
+
+|:exte| |:extenable| +
+||:exte[nable] {extension}|| +
+||:exte[nable]!||
+________________________________________________________________________________
+Enable an extension. {extension} is the extension's name. When [!] is given all
+extensions are enabled.
+________________________________________________________________________________
+
+
+|:extens| |:extensions| +
+||:extens[ions]||
+________________________________________________________________________________
+List all installed extensions.
+________________________________________________________________________________
+
+section:Sidebar[sidebar]
 
 |:sbcl| |:sbclose| +
 ||:sbcl[ose]||

vimperator/locale/en-US/index.txt

@@ -182,10 +182,15 @@ section:Ex{nbsp}commands[ex-cmd-index,:index]
 ||[c]:echomsg[c]|| Echo the expression as an informational message +
 ||[c]:emenu[c]|| Execute the specified menu item from the command line +
 ||[c]:execute[c]|| Execute the argument as an Ex command +
+||[c]:extadd[c]|| Install an extensions +
+||[c]:extdelete[c]||
+||[c]:extdisable[c]||
+||[c]:extenable[c]||
+||[c]:extensions[c]|| List all installed extensions +
 ||[c]:exusage[c]|| List all Ex commands with a short description +
 ||[c]:finish[c]|| Stop sourcing a script file +
-||[c]:frameonly[c]|| Show only the current frame's page +
 ||[c]:forward[c]|| Go forward in the browser history +
+||[c]:frameonly[c]|| Show only the current frame's page +
 ||[c]:hardcopy[c]|| Print current document +
 ||[c]:help[c]|| Display help +
 ||[c]:highlight[c]|| Style Vimperator +
@@ -236,13 +241,13 @@ section:Ex{nbsp}commands[ex-cmd-index,:index]
 ||[c]:setlocal[c]|| Set local option +
 ||[c]:sidebar[c]|| Open the sidebar window +
 ||[c]:silent[c]|| Execute a command silently +
-||[c]:style[c]|| Style Vimperator and web sites +
 ||[c]:source[c]|| Read Ex commands from a file +
 ||[c]:stop[c]|| Stop loading the current web page +
 ||[c]:stopall[c]|| Stop loading all tab pages +
+||[c]:style[c]|| Style Vimperator and web sites +
 ||[c]:tab[c]|| Execute a command and tell it to output in a new tab +
-||[c]:tabdo[c]|| Execute a command in each tab +
 ||[c]:tabdetach[c]|| Detach current tab to its own window +
+||[c]:tabdo[c]|| Execute a command in each tab +
 ||[c]:tabduplicate[c]|| Duplicate current tab +
 ||[c]:tablast[c]|| Switch to the last tab +
 ||[c]:tabmove[c]|| Move the current tab after tab N +