You don't have to move/remove the original LiquidCrystal library that came with the IDE.
Libraries in your user sketchbook area override libraries that came with the IDE as long
as the names of the directories are the same.
So if you name the directory "LiquidCrystal" when you installed fm's LiquidCrystal library
it would override the LiquidCrystal library that same with the IDE.
As a small note:
For the time being, the IDE rejects library directory names that have a dot/period in them
So if you rename a library from foo to foo.sav then the library will not be used.
The only drawback is that you will see a warning when the IDE starts up.
Sometimes this is useful in certain situations or for testing as you can simply rename the directory
and restart the IDE to get the IDE to ignore a library.
So for example, if left the original LiquidCrystal library in place and installed fm's library down in
your sketchbook directory, it would override the IDE LiquidCrystal library if you named it LiquidCrystal.
If at some point you wanted to use the original LiquidCrystal again, if you renamed fm's library directory
to LiquidCrystal.sav then it would be ignored and you would use the original IDE library.
However when the IDE starts it will give you a warning that it is ignoring that library.
--- bill