Old LyX version can cope with degenerated multicolumn cells spanning only one
column, so these should not cause a conversion of the whole formula to ERT.
Such columns are used to set border lines or alignment for single cells.
The math parser could not handle multicolumn grids. This is a problem because
there is no true ERT in math (everything is parsed).
Now multicolumn cells are parsed correctly. The display is also somewhat OK,
but apart from that any multicolumn related UI is missing. Since the file
format change is now done the UI can be added at any later point. The most
important part of bug 396 is now fixed: tex2lyx does not create invalid .lyx
files anymore for formulas containing \multicolumn.
I updated the tex2lyx test cases that produce correct output. tex2lyx does
still produce invalid output for the test cases which are not updated because
of the previous format change.
I don't understand why the string "shadowsize" is not already in the file because when I convert from format 474 to 489 it is added. So why is it not there when I convert from format 474 to 491.
We also get a consistent look with amsmath, so require esint or amsmath.
When resolving alternatives, do also take into account whether the package
is available. For this to work, we also need to test for amsmath.sty (which
was surprisingly not yet done).
The "save-as" part of the bug is fixed by extending the \textclass tag
such that, if a local layout file is used, its path relative to the
document directory is now stored together with the name. If a relative
path cannot be used, an absolute one is used but, in this case, the
document is not usable on a different platform.
The "copy" part is fixed by introducing a new \origin tag, which is
written when the file is saved. This tag stores the absolute path of
the document directory. If the document is manually copied to a
different location, the local layout file is retrivied by using
\origin (which is only updated on save).
This new tag may prove useful also for locating other files when the
document is manually moved to a different directory.
As in the original implementation the files needed for the layout
(for example, a latex class) had to be in the same directory as the
layout file, this directory has also to be added to TEXINPUTS.
Avoid that \newcommand[x] definitions of math macros are pushed multiple
times to the preview loader.
Redefinitions (via \renewcommand[x]) are properly handled.
