Merge pull request #30 from nodiscc/master

add link: in case of empty URL (self-post), prepend "Note: " to the title
add current release version number in shaarli_version.txt
 * release process: please update this file when releasing a new version on github
update check: check against last version available on github.com/shaarli/Shaarli
 * fixes https://github.com/shaarli/Shaarli/issues/5