Changing use, switch, remove behaviour.

Summary:

    from:

        phpbrew use|switch|remove [version]

    to:

        phpbrew use|switch|remove [build name]

Reason:

Since users might have different build with the same version, users need
to explicitly specify the "build name" instead of just the version name.

Affect:

phpbrew use 5.3 won't work, please use phpbrew use php-5.3.3 instead.

Note:

Smart version name guessing can be done later and should depend on the
locally installed versions, should not use the previously used
findLatestMinorVersion() method to detect the installed php.