Merge pull request #9 from Cofyc/master

Clean libsodium submodule entry.
Update Android build script to pick libsodium
Update iOS build script
Rename iPhone target to iOS, because it works fine on iPad and iPod, too.
Add mipsel-linux-static.sh to the distributed build scripts
Disable PIE for Android builds.
Add USE_ONLY_PORTABLE_IMPLEMENTATIONS
Don't print "initializing for optimal performance" if we don't.
Update ChangeLog
Use only portable implementations on iOS.
Check that the list of supported protocol versions the client
advertises is actually supported.
The current proxy only supports version 2.
Sync Homebrew formula
Fix typo
Explain how to check file integrity.
Update TECHNOTES
Print the chosen cert validity period.
Add --test
Don't bind anything in test mode.
-t can now be used to specify a safety margin
Fix --test=