Sync README.DEVELOPER and .travis.yml

Minimize the number and size of dependencies and remove redundant
packages from the list.
FIx windows icons and cursors (Christoph Biedl)

the detection of MS-Windows icon files was buggy and incomplete. Since
non-animated cursors have a very similar format, they are added here,
too.

Some details: Using only the very first four octets for determination
has always some risk of false detection. So additionally look at
offset 9 which should always be zero, but according to Wikipedia might
also be 0xff.

In "number of colors" at offset 8, the zero value previously was used
to describe "256 colors", according to Wikipedia this isn't true, so
it was dropped.

On a side node: This introduces another usage of name/use. I'm afraid
we might sooner or later end up in name clashes on these identifiers.
Feel free to extend them like prefixing with the file name "msdos-".

Also, I was a bit surprised no "message" in "use" is printed, I wanted
to do

    >>4 use     ico-dir     MS Windows icon resource

but that message gets lost. Hence the hackery

    >>0 byte    x           MS Windows icon resource
    >>4 use     ico-dir

So a feature request: Print any message in "use".

This patch by the way fixes Debian#562250. It just got a little
bigger.
Explain date number format (Christoph Biedl)
Add compiled delphi magic
Fix typo.
escape space.
Fix typo another way. Per Christoph Biedl.
Remove explicit autotools-dev.
Sort list of packages for ease of maintenance.
Add ID.
fix bug intruduced by the locale changes.
remove bogus comment
remove debugging printf.
PR/334: don't try to free the magic list if it was not allocated, since this
is an error.
PR/333: Be more precise about counting the strength of a regex, by counting the
number of actual matching characters specified in them.
Fix mime entries that were attached to magic entries that did not yet
have descriptions.
PR/320: Issue a warning for mime types that are attached to magic entries
that don't yet have descriptions.
PR/319: Remove superfluous call to file_ascmagic_with_encoding. file_encoding
should have set looks_text correctly before, and file_ascmagic already calls
file_ascmagic_with_encoding if it needs to.
today's changes
add fmtcheck