Update p5-MMapDB to 0.15.

Changes from previsou:
----------------------
0.15  Mon Sep 10 10:37:44 CEST 2012
      - make "map {local $_} values %{$d->main_index}" work
        map creates an alias ($_) and local tries to assign to it.
        Prior this threw an exception.

0.14  Sun Apr  3 20:57:57 CEST 2011
      - index_lookup and index_lookup_position now accept 0 or undef in
      	place of the index parameter. In this case the mainidx is looked up.
	Should be a bit faster than passing $db->mainidx.
      - index_lookup_records(), index_lookup_values(), index_lookup_sorts()
      - speed up writing: mmap _tmpfh and _stringfh to avoid sysseek+syswrite

        v0.13: 20.7612 (19.09 usr +  1.63 sys = 20.72 CPU) @  1.06/s (n=22)
        v0.14: 20.299 (20.20 usr +  0.05 sys = 20.25 CPU) @  1.68/s (n=34)
                Rate v0.13 v0.14
        v0.13 1.06/s    --  -37%
        v0.14 1.68/s   58%    --

0.13  Thu Mar 31 12:27:39 CEST 2011
      - MMDB-lookup tool
      - data_record, data_value and data_sort now work on a position list
        instead of a single position.

0.12  Sun Oct 31 14:22:53 CET 2010
      - fixed subtle UTF8 problem: 2 strings consisting of the same ascii
      	characters were considered different if one of them had the UTF8
	flag set while the other had not.

	Example:

	  no utf8;      # just to make sure
	  Encode::decode_utf8('hello') eq 'hello'

	In Perl this is true. The MMapDB index_lookup function reported them
	as different up to version 0.11.

0.11  Sat Jun  5 16:37:48 CEST 2010
      - removed _rwdata, since File::Map provides protect() now (since 0.21)
      - avoid lvalue substr() in invalidate since this prevents the
        file map to be destroyed in time.

0.10  Fri May 14 13:58:13 CEST 2010
      - make references to the MMapDB object from MMapDB::_base objects
        (tied interface) weak.

0.09  Mon May  3 19:54:25 CEST 2010
      - declare @attributes as 'our'
      - data_value, data_sort accessors
      - DATAMODE_SIMPLE
      - untie in stop() to break circular refs
TrustedQSL 1.14 beta is now available.
  http://www.arrl.org/trustedqsl-beta-release
Updated online documentation is available via
  http://www.arrl.org/TrustedQSL/tQSL-help/
This is beta version and (pkgsrc) Makefile has redundent lines
for upcoming production version. And this is tested to 'make' only,
'make package' won't complete for the time being, thank you.
Add some note on CMakeGenericSystem.cmake.