releasetools: Add radio images to fastboot packages

Fastboot packages should include radio images, if they exist. Also
generate a flash-radio.sh file if a filesmap file exists to indicate
the partition that a radio image should be flashed to.

Change-Id: Ic3392cc76407408b98aad00f36f4dfa3b9be176b
releasetools: Modify regex for radio files

The filesmap file may contain additional information (such as a
sha1 hash) after the parition name. We should still work in these
cases, but can ignore the additional data.

Change-Id: I0feaa5e94d48fa94b66b6c07e1946674fe703d85
releasetools: Add a newline for radio flashing scripts

When multiple radio images exist, make sure we put a newline at
the end of each flash command.

Change-Id: If113c88eb6dc90d2499f06c12e00494d7266a672