* harbour/source/macro/macro.y
* harbour/source/macro/macro.yyc
* harbour/source/macro/macro.yyh
* harbour/source/macro/macrolex.c
* added support for extended string (e"...") to macro compiler and
strings with embedded ASCII NUL character (chr(0))
* harbour/source/rtl/valtostr.c
* added HB_STRTOEXP() function which converts string item to valid
expression which can be compiled by macro compiler. String may
contain any characters.
* harbour/source/rtl/persist.prg
* use HB_STRTOEXP() for sting conversion and 0d....... for date
constants
* harbour/source/rtl/readvar.prg
* harbour/source/rtl/xsavescr.c
* minor cleanup
