Fixes issue: application.ini can't be found

This issue appears when we execute slimerjs from a symbolic link to it.
We should have the real path of the slimerjs script to give the real path to application.ini
Fixed PhantomJS conformance issue on webpage.injectJs and phantom.injectJs

these function should return a boolean, and they should try to load
the file from the current working directory before trying to load
it from the library path.