Bump PHP current version to 5.5 in Use-the-Current-Stable-Version.md

Signed-off-by: Rogerio Prado de Jesus <rogeriopradoj@gmail.com>
Inform that built-in web server is a 5.4+ feature

Signed-off-by: Rogerio Prado de Jesus <rogeriopradoj@gmail.com>
Merge pull request #276 from rogeriopradoj/php55

Bump PHP current version to 5.5
Merge commit 'upstream/gh-pages' into gh-pages