2.5.1

README changed to Markdown.

Unit tests updated to account for following changes.

Add special consideration for the use of # with zero-dimensional references like =A1:A1#. These are the only type of cell-range references that can have a trailing # without adding one before the :, like is required in =A1#:A2#. In other words, =A1:A2# is invalid in Excel, but =A1:A1# is valid in Excel.

Added a specific scope (keyword.control.conditional.if.excel) for the following core logical flow functions:
IF
IFS
IFNA
IFERROR
SWITCH

Add a specific scope (keyword.operator.logical.excel) for the following core logical comparator functions:
AND
OR
XOR
NOT