Avoids the clutter and maintenance effort associated with providing the
function signature string.

The new NotImplemented macro uses __PRETTY_FUNCTION__ for GNU compatible
compilers otherwise __func__ to provide the function name string.

This reverts commit c5bea524.

This reverts commit b18f6cc1.

- The lineNumber of token::undefinedToken was being changed instead of
  just the lineNumber of the return token.

- use List::first() and List::last() methods as well

- Istream and Ostream now retain backslashes when reading/writing strings.
  The previous implementation simply discarded them, except when used to
  escape a double-quote or a newline. It is now vitally important to retain
  them, eg for quoting regular expression meta-characters.

  The backslash continues to be used as an escape character for double-quote
  and newline, but otherwise get passed through "as-is" without any other
  special meaning (ie, they are *NOT* C-style strings). This helps avoid
  'backslash hell'!
  For example,
     string:   "match real dots \.+, question mark \? or any char .*"
     C-style:  "match real dots \\.+, question mark \\? or any char .*"

- combined subfiles in db/IOstreams, some had more copyright info than code
- OPstreamI.H contained only private methods, moved into OPstream.C

Are these really correct?
   IOstreams/Istream.H:#   include "HashTable.C"
   token/token.H:#define NoHashTableC