* Add usage information to iex.bat
Support command line switch '--help', '-h', '/h' and '/?' to show usage information for iex.bat.
Check argument with '/I' to make the test case insensitive:
This allows showing usage information with '--HELP', '-H' and '/H'.
Use 'setlocal' and 'endlocal' so changes to the environment are local to the batch file
(https://technet.microsoft.com/en-us/library/bb491001.aspx) - so there is no need to un-set __ELIXIR_IEX_FLAGS.
* Use documented syntax 'goto label' - without leading colon before the label
* Support cli switch '/?' to show help
Use label :end to jump to the end of the batch file after showing help text -
so the call to elixir.bat is not executed when showing help.
Use 'setlocal' and 'endlocal' so that the env var 'argc' is local to this batch file.
* Support cli switch '/?' to show help for elixir.bat
Test for cli switch '/?' does not need to be case insensitive.
robi-wan
501f856a23