Remove unmaintained folder README

require-ess/tools/README.md

-iocsh
-====
-
-## E3 Unique Variables
-
-```
-E3_CMD_TOP   : the absolute path where a startup script (cmd file) is
-E3_IOCSH_TOP : the absolute path where the iocsh is executed
-```
-
-For example, one executes the iocsh ```${HOME}``` to call ```e3_local/cmds``` via
-
-```sh
-$ iocsh e3_local/cmds/iocStats.cmd
-```
-In this case,
-```E3_CMD_TOP``` is defined as ```"${HOME}/e3_local/cmds"```
-```E3_IOCSH_TOP``` is defined as ```"${HOME}"```