Also misc. minor cleanups

Since 03e0dd33 the calls didn't return an output count
for the recipes.

Enable the server to request the client to reconnect.

This can be done with the now extended minetest.request_shutdown([reason], [reconnect]) setting.

Replaces while loops with proper getfield calls

The doc and the actual behaviour differed.

Use wide_to_utf8 and utf8_to_wide instead of wide_to_narrow and narrow_to_wide at almost all places.
Only exceptions: test functions for narrow conversion, and chat, which is done in a separate commit.

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

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.

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

Also fix a startup error caused by s_security.cpp

Also, clean up surrounding code style
Replace by-value parameter passing with const refs when possible
Fix post-increment of iterators

This improves performance of MapBlock::raiseModified by a factor of 6.
Also, clean up mapblock.h a bit and inline small functions.

This adds the ability to grab 'slices' of noise calculated by PerlinNoiseMap.
Retrieving smaller slices of noise from the computation result as needed
optimizes memory usage while maintaining a reasonable amount of CPU overhead.