[Ohrrpgce] SVN: teeemcee/8744 Get rid of nulzstr, which was unnecessary

[subversion at HamsterRepublic.com]

teeemcee
2017-05-08 08:31:12 -0700 (Mon, 08 May 2017)
334
Get rid of nulzstr, which was unnecessary

Maybe it was necessary back in 2009, but even FB 0.23 accepts both
NULL and @"" as default zstring ptr arguments. The later is a pointer
to a string of length zero. It turns out that @"" is pretty much never
necessary, because unlike C, FB accepts null pointers as valid length
zero strings.
---
U   wip/common.bi
U   wip/common.rbas
U   wip/util.bas
U   wip/util.bi