* integration/bash: New file.
* eat.el (eat-term-shell-integration-directory): New variable.
Contains path to the directory containing the scripts,
automatically updated when Eat is updated.
* eat.el (eat-exec, eat-eshell-mode): New enviroment variable
'EAT_SHELL_INTEGRATION_DIR'.
* eat.texi (Shell Integration): New chapter.
* eat.texi (Directory Tracking): Refer to 'Shell Integration'.