Add support for tdt_print() and examples/dvb_print_si support.

Use definitions from table 100 of EN 300 468.

Setting of teletext_type and teletext_magazine was 1 bit off, instead
of bits 5/3, bits 6/2 were used.

Add missing desc5f_set_specifier() function and also print the specifier
as hex.

Add missing init and set functions and also fix printing.

Add desc48_set_length() function.

Add missing init and set functions.

Add missing init and set functions and also fix return type of
desc43_get_modulation() function.

Add missing init and set functions. Also print service_type as
hex number.

Due to missing casts the function is not returning correctly the top
8 bits (32-40) of UTC_time field.

The fixed warnings are:
  bitstream/dvb/sim.h: In function "tlv_find_data":
  bitstream/dvb/sim.h:216:5: warning: return discards qualifiers from pointer target type

  bitstream/dvb/sim.h: In function "ecmg_validate":
  bitstream/dvb/sim.h:389:5: warning: excess elements in scalar initializer
  bitstream/dvb/sim.h:389:5: warning: (near initialization for "p_param")
  bitstream/dvb/sim.h:389:5: warning: excess elements in scalar initializer
  bitstream/dvb/sim.h:389:5: warning: (near initialization for "p_param")

  bitstream/dvb/si.h: In function "dvb_string_set":
  bitstream/dvb/si.h:174:9: warning: pointer targets in passing argument 1 of "strlen" differ in signedness
  /usr/include/string.h:399:15: note: expected "const char *" but argument is of type "const uint8_t *"

  bitstream/dvb/si.h:174:9: warning: pointer targets in passing argument 1 of "__strdup" differ in signedness
  /usr/include/bits/string2.h:1303:14: note: expected "const char *" but argument is of type "const uint8_t *"
  bitstream/dvb/si.h:174:9: warning: pointer targets in return differ in signedness

  bitstream/dvb/si.h: In function "dvb_string_get":
  bitstream/dvb/si.h:219:25: warning: passing argument 3 of "pf_iconv" discards qualifiers from pointer target type
  bitstream/dvb/si.h:219:25: note: expected "char *" but argument is of type "const uint8_t *"

  bitstream/dvb/si.h: In function "desc48_get_service":
  bitstream/dvb/si.h:742:5: warning: return discards qualifiers from pointer target type

Replace WTFPL with MIT license.

Acked-By: Christophe Massiot <massiot@via.ecp.fr>
Acked-By: Georgi Chorbadzhiyski <gf@unixsol.org>
Acked-By: Jean-Paul Saman <jpsaman@videolan.org>
Acked-By: Rémi Duraffort <ivoire@videolan.org>

This is to avoid the hack with the CAT table, which doesn't have a descs
"header". So there are new functions descl_* to handle descriptor lists
without length. This change is backwards compatible for all tables except
CAT.