Update from mother - #1

* configure.ac:
  - Replace bug report e-mail address with GitHub issue tracker URL.

* configure.ac, +lib/, +lib/Makefile.am, +lib/wcpcpy.c:
  - Check for wcpcpy() and provide a replacement if missing.
* src/Makefile.am:
  - Add $(LTLIBOBJS) to swath_LIBADD.
  - Use 'subdir-objects' automake option.
* src/filterrtf.cpp:
  - Add optional declaration of wcpcpy() if missing.
  - [FilterRTF::GetNextToken()] Replace wcpncpy() call with
    wcsncpy() and manual pointer advancement, as the pre-calculated
    nCopy already determines the exact characters copied.

Thanks scole_mail for the report via a personal mail.

* Makefile.am:
  - Add 'lib' to SUBDIRS.

* configure.ac:
  - Quote m4 strings in AC_INIT() parameters.
  - Replace AM_PROG_LIBTOOL with LT_INIT.
  - Drop AC_HEADER_STDC as 'autoupdate' suggests.
  - Replace obsolete AC_HELP_STRING() with AS_HELP_STRING().
  - Replace parameterized AC_OUTPUT() with AC_CONFIG_FILES()
    and parameter-less AC_OUTPUT.
  - Update AC_PREREQ() from 2.59 to 2.71.