add a command to set the style on current buffer

This commit adds a LinuxCodingStyle command that applies the kernel
style to the current buffer. Note that the filetype is not checked.

For instance, you can map this command with the following in your vimrc:

    nnoremap <silent> <leader>a :LinuxCodingStyle<cr>

[vd: rename SetLinuxStyle to LinuxCodingStyle.]

refs vivien#2

Author: d-k-c

plugin/linuxsty.vim

@@ -47,6 +47,8 @@ function s:LinuxConfigure()
     endif
 endfunction
 
+command! LinuxCodingStyle call s:LinuxCodingStyle()
+
 function! s:LinuxCodingStyle()
     call s:LinuxFormatting()
     call s:LinuxKeywords()