Tie the cache file to the current configuration

By including the current theme, colorscheme and symbol settings the
cache file will be tied to a specific configuration, and regenerated
when any setting is changed.

.gitignore

@@ -1,2 +1,2 @@
 doc/tags
-Powerline.cache
+*.cache

README.rst

@@ -28,13 +28,6 @@ instructions.
 .. _Pathogen: https://github.com/tpope/vim-pathogen
 .. _Vundle: https://github.com/gmarik/vundle
 
-Important information about caching
------------------------------------
-
-Powerline caches the statuslines by default to improve startup time. 
-**Please remember to clear the cache after changing any settings!** Run 
-``:PowerlineClearCache`` and restart vim to clear the cache.
-
 Screenshots
 -----------
 
@@ -91,7 +84,7 @@ I'm unable to patch my font, what should I do?
 The Syntastic/Fugitive statusline flags don't work!
     These flags should work without any configuration. If you installed 
     either plugin after Powerline, you'll have to clear the cache using 
-    ``:PowerlineClearCache``.
+    ``:PowerlineClearCache`` and restart vim.
 
 The colors are weird in the default OS X Terminal app!
     The default OS X Terminal app is known to have some issues with the 

doc/Powerline.txt

@@ -89,11 +89,13 @@ It's recommended that you enable the cache, as this dramatically improves vim
 startup time after the cache file has been generated (the plugin usually loads 
 within ~100ms without the cache and ~1ms with the cache).
 
-Note: You need to clear the cache after changing any Powerline settings. Run 
-":PowerlineClearCache" to clear the cache and restart vim for the changes to 
-take effect.
+Note: The default cache filename includes the current theme, colorscheme and 
+symbol settings in order to tie the cache file your current configuration, so 
+the cache file will be regenerated when you change any settings. This may 
+leave several old cache files in your vim folder, and these may safely be 
+deleted.
 
-Defaults: "<plugin directory>/Powerline.cache"
+Defaults: "<plugin_directory>/Powerline_<theme>_<colorscheme>_<symbols>.cache"
 
 ------------------------------------------------------------------------------
 4.2 Powerline_cache_enabled                          *Powerline_cache_enabled*
@@ -124,9 +126,6 @@ Symbols can be inserted into statuslines by using the following variables:
 
 Default: "compatible"
 
-Note: You'll need to delete the |Powerline_cache_file| after changing this 
-option for the changes to take effect.
-
 ------------------------------------------------------------------------------
 4.3.1 Compatible symbols                        *Powerline-symbols-compatible*
 

plugin/Powerline.vim

@@ -15,14 +15,22 @@
 		\   'theme'        : 'distinguished'
 		\ , 'colorscheme'  : 'distinguished'
 		\ , 'symbols'      : 'compatible'
-		\ , 'cache_file'   : simplify(expand('<sfile>:p:h') . '/../Powerline.cache')
 		\ , 'cache_enabled': 1
 		\ })
 
 		if ! exists('g:Powerline_' . key)
 			exec printf('let g:Powerline_%s = %s', key, string(value))
 		endif
 	endfor
+
+	if ! exists('g:Powerline_cache_file')
+		exec 'let g:Powerline_cache_file = '. string(printf('%s/Powerline_%s_%s_%s.cache'
+			\ , simplify(expand('<sfile>:p:h') .'/..')
+			\ , g:Powerline_theme
+			\ , g:Powerline_colorscheme
+			\ , g:Powerline_symbols
+			\ ))
+	endif
 " }}}
 " Autocommands {{{
 	augroup Powerline