Ox 6: new features and fixes

The Ox version number is kept in line with the OxMetrics front-end version.

Fixed problems in version 6.3

Fixed: When running Ox code in OxMetrics: call to SaveDrawWindow could crash under Linux and OSX.
Fixed: reading of csv with one column and no label treats first number as label: now read as unlabelled.
Fixed: reading "%C" format using sscan/fscan did not always work correctly.
Fixed: xlsx: empty cell (i.e. specified cell without content) would be read as zero.
Fixed: static virtual and virtual static now flagged as error.
Improved: DrawTitle(i, ""); now removes the existing title.

Fixed: problem using for(;;) when it is the first statement in a function (i.e. there are only declarations without assignments before it).
Fixed: A scan format using * to suppress assignment of the read variable did not work for matrix or token types.
Fixed: problem using public static variables in base class, which are accessed via an object of a derived class. class Ca { public: static decl sm_a; static Set_a(const a); } Ca::Set_a(const a) { sm_a = a; } class Cb : Ca { } The first two approaches did not work for a derived class when using static variables in the base class:
1. Public access through an object did not work:
2. Printing an object directly or using "%v" did not work:
3. Access through an object using a `getter' function worked fine:
4. Access using the class directly worked fine:
5. Access using the class and a static `getter' function worked fine: Note that 4 and 5 are more efficient than 1 and 3, because the variable can be resolved at compile time.

New: Added hyper_2F1(a, b, c, z) to compute the Gauss Hypergeometric function ₂F₁ with real parameters a, b, c and real argument z.
Improved: exit now exits with the specified return code (in a console)
Improved: polygamma now allows negative arguments
Improved: xlsx: allow reading of strings created through a formula
Improved: xlsm can be read as xlsx
Fixed: Save graph as PDF: hats on symbols showed next to the symbol; large ellipses were squeezed in the middle.
Fixed: xlsx: column labelling error when > 26 columns. Reading file written by OxMetrics works, but there are gaps. Reading file written in Excel will result in skipped columns.
Fixed: There was a bug in some quantile functions that could lead to return of wrong value in some rare cases. This could affect quantiles of F, Beta and Inverse Gaussian.
Fixed: Chrome/Safari/Opera frame loading fixed (was entering infinite reload loop). Improved default browser detection under Windows. Improved Chrome/Safari jumping to help item.

New: Added read and write support for Excel xlsx files. Added read (113,114) and write (114) support for Stata 11 .dta files.
New: Added PDF as new save format for graphics.
Changed: Now using thinner symbols on very thick lines in plots.
Fixed: PostScript BWG did not obey BWG line types
Fixed: dev/.../Makefile files were missing from the installation.
Fixed: SetTextWindow could appear to be delayed relative to the output, so output from the previous window could show in the new one.
Fixed: This wouldn't work from OxRun (from draw4.ox): ShowDrawWindow(); // show this concoction SaveDrawWindow("draw4.gwg"); SaveDrawWindow("draw4.eps"); The second graph would not be created, and would create an empty draw4 window.

Added QQ_N_SE for DrawQQ: pointwise asymptotic Std.Error bands on normal QQ-plots.
Recession shading line style (style constant is ST_SHADING; shading is on when the variable has value 1, off otherwise).
oxdraw.h: defining ST_
Introduced oxo version (separate from Ox version), current version is 5 (unchanged from Ox 5 to Ox 6). When the oxo version changes, .oxo files must be recompiled.

OxPack: fixed potential issue in "OxPackSpecialDialog"("OP_VARIABLE",...
Repeatedly running an Ox file that saves a graph could result in multiple instances of the same graphics files being open in OxMetrics (asking for a reload every time it changes).
The following code would leak memory: Because invertsym wouldn't free before assigning. This applies to a few library functions that return an integer or double through an argument (and was only likely if a variable was reused).
PcFiml class lacked GetResVar() (virtual from Modelbase)
DrawAdjust doesn't work for DrawDensity because the title is drawn after the density.
MaxSQP(F): didn't return MAX_MAXIT if max reached; rounding errors on Hi/Low bounds could push parameters outside bounds by a tiny bit.

This file last changed .