Ox 2.20: new features and fixes

New features and enhancements

Minor adjustment to GiveWin for Windows 2000.
OxPack with always on top option. Now installed with Ox Professional in ox\bin.
invertgen(.,30) now distinguishes between singular and negative definite matrix.
sortc of T x 1 matrix now same speed as sortr.

Fixed bug in OxMainCmd which affected the Visual Basic RanApp example.
Assigning member functions to a variable could lead to problems if reassignment of the variable to another member function is made.
Modelbase: keeping sign on t-values.
automatic creation of backup files when saving data has been removed.
sscan with %c format could return too much text.
Spreadsheets: now writing "#N/A" for missing values in Excel files; @NA in Lotus 1-2-3 files.
Problem with reading dates from data.xls: doesn't pick up dates when date column is unlabelled.
Compile only: returns exit code !0
choleski(): doesn't return 0 when decomposition fails. Also made choleski() fail at same point as decldl(): checking a[i][i] rather than sqrt(a[i][i]).
PcFiml class Chow(): if break-point beyond sample: would give .NaN because m_dLogLik was cleared by Modelbase::SetSelSample().
Note: QuadPack is compiled FORTRAN. Consequently call backs are non-re-entrant, and a QuadPack function cannot call the same function. However, now it can call a different QuadPack function, allowing for double integrals.
Database class: Lagged seasonals are actually leads, so: Season_1 is Q4, Season_2 is Q3, Season_3 is Q2.
Removed artificial upper limit on line length (format function).
DrawTitle doesn't replace an existing title. Fixed in GiveWin.
When starting OxRun from GiveWin, it may loose the last section of output.
Small fix in lib/longrun