Version number for the v5.3.5 release
Switch build to the new machine.

(cherry picked from commit ed1ebce60ac9b238a94a8b0e24ceb27c598f5733)
Distribute realm.

(cherry picked from commit 0b50080cd14ca5471a28392736d7a6f528df1787)
Ubuntu machines got upgraded.

(cherry picked from commit ff70e036a22850481aa4197ffeb68fe15be06638)
New Racket version 5.3.5.
Updated sizes of repackaged source distributions.

(cherry picked from commit 108504597300f9fcaa24c0445c51f624ccfe2a3f)
Fix inclusion of "keep-dirs.rktd".

The file should be considered as source even though it's in the "doc"
directory.

(cherry picked from commit 039751853993cf426ae0a27eb26078ef3f96880d)
Drop todo file.

(cherry picked from commit c37ce33baad0ca2f8d63fa0e75608f39422f70a3)
typos in source documentation; thanks Laurent, OEV

(cherry picked from commit 2de0c7270cd9d34972673e62d7c1bff2eb91f5da)
v5.3.5 installers info

(cherry picked from commit 61b509d39e5fae58a8c26633d149ecb34991c034)