Introduce BundleBind! command to speed up Vim startup

The performance issue was introduced in 55a5ef04.

autoload/vundle.vim

@@ -7,6 +7,9 @@
 com! -nargs=+         Bundle
 \ call vundle#config#bundle(<args>)
 
+com! -nargs=0 -bang BundleBind
+\ call vundle#config#bind()
+
 com! -nargs=? -bang -complete=custom,vundle#scripts#complete BundleInstall
 \ call vundle#installer#new('!' == '<bang>', <q-args>)
 

autoload/vundle/config.vim

@@ -1,8 +1,11 @@
 func! vundle#config#bundle(arg, ...)
   let bundle = vundle#config#init_bundle(a:arg, a:000)
-  call s:rtp_rm_a()
   call add(g:bundles, bundle)
-  call s:rtp_add_a()
+endf
+
+func! vundle#config#bind()
+  call s:rtp_rm_a()
+  call vundle#config#require(g:bundles)
 endf
 
 func! vundle#config#init()

doc/vundle.txt

@@ -108,6 +108,17 @@ equals full uri >
 
 NOTE: Vundle defaults to http:// protocol for the short URIs
 
+                                                            *BundleBind!*
+`Bundle` command just tell Vundle which scripts you want to use, it doesn't
+tell Vim load them, i.e, it doesn't update the 'runtimepath' option of Vim.
+
+To tell Vim load your scripts, `BundleBind!` must be executed. But Vundle will
+do it automatically, so usually you don't need to do it yourself.
+
+The benefit of use an extra command to update 'runtimepath' is, we can make
+Vim startup much faster while keeping 'runtimepath' ordered according to the
+bundles declarations.
+
 
 4.2 INSTALL SCRIPTS ~
                                       *vundle-scripts-install* *BundleInstall*

plugin/vundle.vim

@@ -0,0 +1,7 @@
+if exists('g:loaded_vundle') || &cp
+  finish
+endif
+let g:loaded_vundle = 1
+
+" Bind and load all scripts bundles immediately.
+BundleBind!