* Use enum for GENERIC_CMD_*
* Rename m_attachements to attachement_parent_ids (public member and clearer name)
* Rename GENERIC_CMD_SET_ATTACHMENT to GENERIC_CMD_ATTACH_TO
* USHRT_MAX + 1 buffer sizes to prevent overflows as @kahrl suggested
* Remove unneccessary m_id from GenericCAO (shadowing protected superclass member for no reason) as @kahrl suggested

Also fix UTF-8 inner byte bounds and make unittest for case this fixes.

Also count multibyte sequences as "one" character.
Adds unittest for the bug reporter's case.
Fixes #2796.

No freezing when inbuf_size doesn't decrease over time.

* Make method (more) consistent with current code stlye
* Move index into loop constructor after @rubenwardy's suggestion
* Cache inv_s->getList(s.listname), which removes a possibly bad scenario
of inv_s being null.
* Properly check for validity

Adds list-rings, a method to implement item sending between inventories via shift-click.
Nice insider feature: a ring consisting of a single inventory list serves as nice clean-up method.
Also adds them to minimal game, and the standard inventory.
Craft output slots are not supported.

Decorations: Remove lower limit of water level for placement

While utf8_to_wide works well, wide_to_utf8 is quite broken
on android, for some reason.

According to doc, dofile() raises an error when parsing failed due to syntax errors.
Fixes #2775

Treegen: Remove alias checks from jungletree generation for speed

If you run minetest with valgrind, you'll quickly notice uninitialized jump
depend error messages that point to s_base.cpp:131. This commit fixes those.

Spare direct multoplication, use constant MapBlock::nodecount instead of
local nodecount variables.

Also use strides at one place instead of multiplications.

ObjectRef:
get_properties
get_armor_groups
get_animation
get_attach
get_bone_position

Players:
get_physics_override
hud_get_hotbar_itemcount
hud_get_hotbar_image
hud_get_hotbar_selected_image
get_sky
get_day_night_ratio
get_local_animation
get_eye_offset

Global:
minetest.get_gen_notify
minetest.get_noiseparams

Parent commit broke behaviour.
Thanks @TeTpaAka for testing the fix.

Mgv6: Enable snowbiomes by default. Double biome noise spread. 3 octaves, 0.5 persistence for humidity

Use v arrows except where there is only one line between two boxes,
and other improvements
(Yea could use ↓ but its an ASCII art not an Unicode art).

Mgv5/v7: Fix generateBiomes biome recalculation logic Biomegen down to y = -192 for mgv5 deep oceans. Improve code

Also fix a startup error caused by s_security.cpp

Thanks to @UltimateNate for pointing this out :)