Cherry-pick most commits since 15c0376

Commits not directly related to network changes were cherry-picked
on a best-effort basis, as some cause difficult merge conflicts.

Commits skipped over:
0d1eedcccc
aa474e4501
82482ecd9d
b214cde5b4
2066655aae
7e088fdfe3
40bf1d7b5f
1b2f64473e
7e56637ed0
64ff966bae
51057a56f5
009149a073
cf4045ff0f
e357577cb2
49f84b76bc
b019221c30
7880ff74b6
146f77fdb7
a704c04f00

Commits with conflicts:
038d3a31df
e9eda2b0d0
708337dfc2 ~~ modified client.cpp manually; shadow changes to packethandlers/client.cpp
36e8ba9ce2 ~~ modified main.cpp manually; add ALLOW_ZWRITE_ON_TRANSPARENT set
3b6480c5b0 ~~ modified server.cpp manually; change wrapDegrees -> modulo360f
5a5854ea9d
c09d026f05
3c91ad8fc2

doc/menu_lua_api.txt

@@ -1,4 +1,4 @@
-Minetest Lua Mainmenu API Reference 0.4.11
+Minetest Lua Mainmenu API Reference 0.4.12
 ========================================
 
 Introduction
@@ -197,9 +197,11 @@ core.delete_world(index)
 Helpers:
 core.gettext(string) -> string
 ^ look up the translation of a string in the gettext message catalog
-fgettext(string, ...) -> string
+fgettext_ne(string, ...)
 ^ call core.gettext(string), replace "$1"..."$9" with the given
-^ extra arguments, call core.formspec_escape and return the result
+^ extra arguments and return the result
+fgettext(string, ...) -> string
+^ same as fgettext_ne(), but calls core.formspec_escape before returning result
 core.parse_json(string[, nullvalue]) -> something (possible in async calls)
 ^ see core.parse_json (lua_api.txt)
 dump(obj, dumped={})
@@ -211,6 +213,12 @@ string:trim()
 core.is_yes(arg) (possible in async calls)
 ^ returns whether arg can be interpreted as yes
 
+Version compat:
+core.get_min_supp_proto()
+^ returns the minimum supported network protocol version
+core.get_max_supp_proto()
+^ returns the maximum supported network protocol version
+
 Async:
 core.handle_async(async_job,parameters,finished)
 ^ execute a function asynchronously