These patches improve a few inconsistencies in how Eshell conditionals 
work, especially when using Lisp forms inside of the command-form of 
"if". For example, before this patch, the following command outputs 
nothing at all:

   if (zerop 0) (identity \"yes\") (identity \"no\")

With the patches, it now correctly outputs "yes".

I also added the ability to use the "else" keyword so that you can chain 
together if/else blocks like so:

   if {[ -f file.txt ]} {
     echo found file
   } else if {[ -f alternate.txt ]} {
     echo found alternate
   } else {
     echo not found!
   }