Create "exec" mapper that sets executable bits

[ctron]

It would be nice if there would be a new "exec" mapper that simply sets exec bits only.

Configuration:

<mapper>
<type>exec</type>
<incldues>myapp</includes>
<user>true</user>
<group>true</group>
<other>true</other>
</mapper>

All files matching that expression get the exec bit set.

[ebourg]

Rather than adding a new mapper I think we should implement something like dh_fixperms, such that in most cases we never have to care about the permissions on the files.

http://man.he.net/man1/dh_fixperms

[ctron]

Well this would be even better. But I though it would also take much longer.