GSoc Applicants: submit the final proposal

[Ondřej Čertík]

Dear GSoC Applicants,

Please submit the final pdf now. I went through applications that are
open at https://summerofcode.withgoogle.com/, and most of them say
"Status: incomplete". You have to submit the final pdf to turn the
status to "complete", before tomorrow. Otherwise the SymPy
organization can't accept you and you will not be considered.

Do not leave this to the last minute, in case the online application
stops working tomorrow (it has happened in the past due to too many
people accessing it at the last minute).

Thanks,
Ondrej