Fix for 'function already exists' error

Added !'s to the func definitions.

I mistook the following error for a plugin conflict, but it happens when the script gets re-sourced by Vundle after running :BundleInstall!

> Error detected while processing /Volumes/Storage/Dropbox/dev/vim/bundle/vim-php-namespace/plugin/phpns.vim:
E122: Function 74_searchCapture already exists, add ! to replace it
E122: Function 74_saveCapture already exists, add ! to replace it