The new function is X(SRC,REF), which briefly for a cell in the neighborhood
of REF returns the corresponding cell in the neighborhood in SRC. For
further details, see the updated documention.
In developing and documenting this function, I refined some of the
existing error messages (e.g. showing the coordinates when there is an
attempt to obtain a cell with a negative coordinate) and improved the
error propagation to increase the chance that the innermost error will
percolate to the top level.
Provides additional keys to clock and reset the spreadsheet in GUI mode.
Updated LyX manual to include GUI mode keys, including the new ones, to
include some of the more recent features like bold and highlight, and
also improved some phrasing throughout.
Fixes#4.
