`apply_filter` becomes obsolete
Add old API support with warning messages when exit
Add Filter Implementation Guide
Add sample files for all supported filetypes except nerdtree
Improve regexp for C/C++

whitespaces can be placed after a function name
int main () {
}
Add check for g:ctrlp_funky_sh_type

if invalid sh_type is specified it would be assumed to be 'bash'
Add anonymous function support for zsh