Refactored stairs rendering to support corners
Added some icons for people to use in their POIs.
Moved icons to subdirectory, adjusted docs

I also added one of the icons to the manualpois example, so people
have an exmaple of how they can use these in their configurations.
Fix error reporting in genpoi when a bad dimension is specified
Update config.rst

Fix typo in example code that causes error in an actual config file.
Item list update
Merge pull request #998 from Disassembler0/master

Item list update
Merge PR #997
Fix additional typos in docs (thanks tomthorogood)
Merge PR #991
Add warning to index.html that should hopefully be visible when there is
an error loading the JS components
Fix transparent check for block ids > 255. (getArrayByte3D -> getArrayShort3D)
Merge pull request #1006 from maruohon/blockid-range-fix

Fix transparency check for block IDs > 255
Merge PR #989 -- Refactored stairs rendering to support corners
Merge branch 'snapshot'

Conflicts:
	overviewer_core/src/iterate.c
Bump extension version
Add Acacia/DarkOak wood
Add stained glass and stained glass panels

Note that this commit changes the pseudo-ancil-data type from unsigned
int to an unsigned short.  Our pseudoancil code creates 5 bits of data
to store adjacency information for glass.  Glass also has 4 bits for
color info.  This means we need a total of 9 bits to render these (thus
int --> short)
Fix a oops with water