Add default value
Rename argument
Explicit verification of relative bower path
Add example
Old keyword name used in example
BUGFIX: tilde expansion actually useless on relative paths
Modify relative_execpath default value as suggested
Added version_added for relative_execpath
Update for last few comments on the bug report
* version to 2.1 since this feature enhancement will now go into 2.1
* set path and relative_execpath type to path
* Set default value of path to None