Small documentation update.
First nearly working version.

This now produces working incremental updates for simple
block mode updating. Everything else is disabled.
Move point to change location.

Previously, we were dependent on the current location of point
which is not guaranteed to be the same as the change for bulk changes
to the buffer such as rectangle operations.
Initial incorporation of incremental change.

This sort of works -- the updates are happening incrementally,
but wrongly.
Convert start point before changes.

We need to work out whether we should insert new changes in that-buffer
before the changes happen to this-buffer, or our conversion function has
to cope with inconsistent buffers.
Stop location now calculated from before functions.
Tests uncommented, and expected failures added.
Pabbrev support dropped.

Pabbrev now uses the after-string overlay property and so does not
actually add anything to the buffer when an expansion is offered. As a
result, pabbrev support is not needed any longer.
Add long test file.
Fixed some errant blocks.
Dependency updates.
Add string transform function.

Provides a function that is useful for advicing.
Logging alterations.
Incremental updates for block mode.

Mostly this enables incremental updates. There is a fix to convert which
depended on the value of point. Pabbrev support has gone (because it's
not needed any longer).

This commit includes too many things!
dev options added.
Add support for logging non-matching buffers.
Removed :numeric option.

We replace from start to finish, so this breaks everything.
Nil markers after use.

Block commenting creates a lot of markers which may well damage
performance in the buffer until GC happens, so nil them all as we go.
Switch to exact-subtract.

It should be faster in many cases.
Cosmetic Change