Adding gemified version of rb_pgplot
Fix va_arg bug/crash on some 64-bit patforms

Calls to rb_scan_kw_args terminated the variable arg list with 0, but
that caused errors on the platform described below.

The problem appears to be that 0 gets passed via va_args as a type with
a different (smaller) size from "char *", which is the type used to
extract the arguments with va_arg.  This caused the va_arg processing
loop to run past the end.

The solution is to be sure to cast the final 0 argument in
rb_scan_kw_args calls as (char *).

Here is some info describing the patform where this problem was
discovered and fixed...

$ uname -a
Linux paper1 2.6.31-20-generic #58-Ubuntu SMP Fri Mar 12 04:38:19 UTC 2010 x86_64 GNU/Linux

$ gcc --version
gcc (Ubuntu 4.4.1-4ubuntu9) 4.4.1
Copyright (C) 2009 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Bump pgplot gem version to 0.1.3.1
Do not check or link unecessary libraries
Bump version to 0.1.3.2
Add README.rdoc
Updates for Ruby 1.9
Change access to range limits

The limits of ranges used to be obtained via "rv_ivar_get", but this does not
work in 1.9.2.  This changes it to use rb_funcall instead.
Bump version to 0.1.3.3.
Add .gitignore
Merge masa16 and davidm "branches"

Both masa16 and davidm starting tracking in git from rb_pgplot 0.1.3.  Both had
changes.  Now these parallel development paths are merged back into one!
Move extension source code to ext/ subdirectory

This avoids a potential installation problem where the "install" program
sometimes refuses to install a file (pgplot.so in this case) on top of
itself.  This can happen when using rubygems to install.
Clean up README and FuncUsage for prettier output

Cleans up the RDoc formatting of README and FuncUsage so that the
output generated by RDoc (e.g. when installing via rubygems) looks
nicer.
Mention Ruby 2.0.x support in README
newfile: ext/version.h
add to .gitignore
revert checking in extconf.rb
Bug: need ch[0], not ch. New: Pgplot::VERSION
read version.h, etc.