Added ${2: `!v g:snips_author`} to snippet 'class'

The php.snippet was changed on line 219 to:
"@author ${2:`!v g:snips_author`}", to insert author name for php classes.
Merge pull request #114 from nanyaks/master

php: Added ${2: `!v g:snips_author`} to php 'class' snippet