modified synthesise: added underscore on property name.
added ibameth_full snippet (to add a method in one command, declaration and implementation.
Obvius you need to cut/copy from .h to .m
added if - else  if - else snippet.
renamed property retain readonly snippet with prr instead pro
added "property nonatomic weak" snippet (pw)
deleted some (IMHO) not very usefull snippet.
Merge pull request #1 from ignazioc/master

some new snippet from 'ignazioc'.