1. use apt-get instead of apt as apt API is not stable
2. use 1 line per argument to follow docker best practise
3. use wget instead of ADD to ensure ff14.zip is not download during
each build run (it is save to assume ff14.zip never changes)
4. only COPY source files need for build instead of entire repository
fixed the valgrind warning:
Conditional jump or move depends on uninitialised value(s)
at 0x11271E: check_fs (ff.c:3301)
by 0x1127C7: find_volume (ff.c:3325)
by 0x1129B0: mount_volume (ff.c:3427)
by 0x112FAD: f_mount (ff.c:3680)
by 0x10D7DC: main (main.c:139)
cast size_t to unsigned to avoid issues caused by
64 bit systems mixed with 32 bit once.
cast pointer to unsigned long to ensure 64bit will
be printed on linux x64