Add workaround code for facebook ads api server error. Related bug report - https://developers.facebook.com/x/bugs/241617149351663/
Remove print statement for debug.
Merge pull request #1 from taenyon/debug

Remove print statement for debug.
Update version info v0.1.24 in setup.py.
Modify workaround code of commit '7eec43edb55b0b3fcab1623aa1e0d86b0e25a111'
Modify string type of workaround code.
Modify string type of workaround code.
Modify workaround code for facebook server error.
Modify workaround code for facebook api server error.
Modify error code and message for facebook api server error.
Merge pull request #2 from taenyon/master

Convert 'None' data to error code for facebook internal server error.