George Kadianakis:
I think currently the only way to get tor-0.2.5.1 is to use the git master. Feel free to ask any questions you have.
You are forgetting the automated Debian package builds (thanks weasel!).
Putting the following in /etc/apt/sources.list will do it:
deb http://deb.torproject.org/torproject.org tor-nightly-master-wheezy main
Replace “wheezy” by one of precise, quantal, raring, saucy, squeeze, jessie, sid depending on your distribution.