ram_blk: change blocksize output to decimal

Reading 200 instead of 512 is confusing.
dde_rump: fix compiler int cast warning

Use long instead of int.
dde_rump: block encryption server using cgd(4) [WIP]
first steps towards Block::Driver
ram_blk: remove superfluous block_number check

block_number is Block::sector_t (uint64_t), which never can by less
than 0.
minor Block_driver adjustments
fix compiler warnings
dde_rump: implement rumpuser_dprintf()

Though we do not need this function, it is helpful while debugging.
rump_cgd: add base64 decoding
rump_cgd: enable WRITE

Apparently, we need to enable write support — otherwise rump will refuse
to open the block device (see sys/rump/librump/rumpvfs/rumpblk.c:360).
rump_cgd: add ext2 on cgd runscript
ports: simple file system test running in noux

By running one of these run scripts a user-defined shell script will
be executed within in noux, which conducts the defined file systems
tests for given File_system_session based file system.
disable automatic start of the test script
add fs test script using rump_cgd + rump_fs
tool: add makefile for building rumpkernel tools

The rumpkernel tools are used within the Genode OS Framework tool chain.
tool: rump wrapper script
fixup rump_cgd
dde_rump: use tool/rump in cgd runscript
f rump_cgd #2
dde_rump: use libc_vfs in rump_cgd_ext2 runscript