Use escaped grep command, skipping aliases
Use 'local' in functions
Various improvements

 - Support for leave event, via DOTENV_FILE_LEAVE and _dotenv_event (can
   use DOTENV_FILE_LEAVE=$DOTENV_FILE_ENTER).
 - Support for searching upwards for $DOTENV_FILE_ENTER (#3).
 - Source .env only once per session, but re-source when leave events
   are enabled (#1).
 - Trigger the machinery when the script gets sourced, for the current
   dir (#2).
Add a test for DOTENV_HANDLE_LEAVE=0
Cleanup, and fixes (absolute path for env_file)
Check for file existence in _dotenv_check_authorized_env_file
Wrap sourcing in _dotenv_source: chdir and set _dotenv_cwd=$PWD
_dotenv_source: use 'builtin cd' and stored dir instead of 'cd -'
doc / small refactoring according to feedback
Use 'test' as target for tests (common sense)
Merge pull request #4 from blueyed/improvements

A lot of improvements, based on coming from "smartcd"