Command substitution file parameters.

I just finished implementing the file option to command substitution. This is the same syntax that bsh/ksh use.

In 0.0.1.4 you can use the expression $(<file)

a=$(<file.txt)

then words are not expanded so that $a is a single string but when used in an argument list such as

set $(<file.txt)

words ARE expanded. The behaviour can be forced to not expand by using quotes such as

set "$(<file.txt)"

In the next release will be the similar, but admitedly clumbsy syntax of $<(<file.xml).