updated certificates in tests/_samples and added script to update

removed encrypt.p12 and sign.p12 as these are not used
added .gitattributes to fix wrong line-endings for crt, key and srl
Change preg_replace /e to preg_replace_callback
to avoid a deprecated warning in test-suite
Remove filter when unbinding

Solves Bug #400 #252 and possibly others
Use variable name more consistent with other input streams for unbind functions
updated CHANGELOG
Add Travis
updated CHANGELOG
prepared the 5.0.3 release
bumped version to 5.0.4-DEV
Updated hex2bin replacement for php 5.3