Change TileSpec::frames to be std::vector not std::map

Signed-off-by: Craig Robbins <kde.psych@gmail.com>
Re-add hacky fix for underwater grass, to fix mgv7 user's biomes
lua_api.txt: improve noise documentation. Remove previous eased 3D noise format example
Fix weird (and wrong) comment in test.cpp
Regenerate server_flags_creative.png from XCF
Temporarily fix always bright wieldhand with shaders enabled
Update mapgen stuff in minetest.conf
Make limiting of the reflow liquids queue size optional

If liquid_queue_purge_time == 0 then disable the queue size limiting and make this the default setting
Additionally, liquid_loop_max now defaults to 100000
Silence misc. warnings
Update MinGW toolchain downloads used by travis
Conf.example: Fix typo