remove outdated TODO

This was implemented in fe2d1fb955035bb28126c4f7dc18036eb99e42d9.
discid: also display track durations in minutes and seconds

Example:
Track 1       :      150    22310 (04:57.47)
Track 2       :    22460    27737 (06:09.83)
Track 3       :    50197    30417 (06:45.56)
Track 4       :    80614    20214 (04:29.52)
Track 5       :   100828    32490 (07:13.20)
Track 6       :   133318    11394 (02:31.92)
Track 7       :   144712    20188 (04:29.17)
Move sectors to time code to its own function.

Use it for total length as well as tracks.
Use "sector" instead of "frame" to be consistent.
Merge branch 'discid_track_duration'

see pull-request #25
update AUTHORS
some stylistic fixes for discid

discid_new() is important so it shouldn't be hidden in the declarations.
The other things are just style/names.
make room for hours in discid example

Additionally, 2 digit hours are impossible on audio CDs.
Linux: fix minor valgrind warnings

The mcn struct might not be filled correctly by the ioctl.
The free in discid/isrc is mainly to remind the user to not forget it,
even if the program exists right afterwards.

Both don't have an actual impact.
fix valgrind warnings on other platforms

I only checked FreeBSD with valgrind and made the other changes as they
seemed fitting.
Valgrind doesn't work as well on these platforms, FreeBSD might be the
best of these.

Again, all of these were no real problems, but fixing warnings
in valgrind might help when real issues occur later on.
LIB-26: add a simple test with a disc

This basically replicates the testing already done in python-discid.

I implemented several helper functions. That should pay off when adding
more tests and using these in the build test suite.
LIB-26: use testing functions in both tests
use noinst_HEADERS for all internal headers

Not really sure why these have been in libdiscid_la_SOURCES before
and I hope this doesn't break somehow.
LIB-26: run test_disc, but skip it without disc

Autotools supports a return value of 77 to skip the test
so we do that.
Cmake doesn't support testind directly anyways so we have
to catch the return type 77 manually.

return values other than 0 and 77 should lead to errors of course.
LIB-26: split tests to core, put and read

One program is one test for autotools so we should split that up
to give reasonable output.
FAILED: test_discid
wouldn't give much information on what failed.
change test_read to the new testing schema

This means we can get rid of the msg parameter and assert_true.
LIB-26: test full read (with MCN + ISRCS)

We can only check that nothing invalid happens.
Discs might not include any MCN or ISRCS, even if libdiscid works
correctly.
use get_default_device in discisrc example
LIB-26: test error_msg, features and feature_list

Error message should be available when something failed and otherwise
empty.
Features are tested for consistency with the feature list and the actual
output on read.
fix discid example for MSC/MSVS

snprintf needs fixes like in the internal code.

See also #25, where snprintf was added to the example.
add tests for get_default_device

We also anticipate tests for empty objects,
which wouldn't work right now so it is disabled.