installing drush via Composer, rather than using PEAR.
adjusted path to drush.php.
let's try fixing that path to drush.php again, shall we?
correct path to drush executable, and the path to drush.php once more.
added composer's global bin directory to PATH, then shortened paths to drush executables.
gotta keep the full path to drush.php, fixed.
KISS: only export composer's bin dir to the path.
Merge pull request #3 from stopfstedt/composerize-drush-installation

Composerize drush installation