Appease make check-spaces
Add changes file for bug #11235
Work on the changelog for 0.2.5.3-alpha some more
copy-edit the 0.2.5.3-alpha changelog even more
fix a few grammar things, and deprecate 'servers' and 'nodes'

also clarify a few explanations. so far so good!
use the formatting from 0.2.4.21 for the 0.2.4.21 changelog stanza
missing colon
sort stanzas by interest, and sort by version within stanzas

(users want to know about client fixes before they want to know about
unit test fixes.)
extract some changelog principles into doc/HACKING
Merge remaining changes/* items into ChangeLog

(Not taking bug11235 since it's a whitespace fix)
Fix unittest compilation with --disable-curve25519

This is a fix for 9700, which we already fixed in 0.2.5.x, but which
got left in 0.2.4.x.

This is a partial backport of a0a855d586d99540277014ccd3
Merge remote-tracking branch 'origin/maint-0.2.4'

This is an "ours" merge, taking nothing, since we already had the
changes that were in a83abcf5ee5cb8fe245bc97e0