Updating Block event with reference to Voxel

Updated `BlockEvent` with `Voxel getVoxel()` for block/position. I'm debating
renaming the events to `VoxelEvent` but that may be too different from
what devs are accustomed to.
Update JavaDocs, Game, World
Add cancel based methods to event base interface
Add ItemsStack interface, without any Inventory
Update README.md, Forum Link
Fixed javadoc, added missing @Overrides

I accidentally deleted this

I'm tired, I screwed up a few things

I'm tired, I screwed up a few things
Fixed Javadoc describing Order.BEFORE_POST and Order.POST to be cancelable. Fixes #98
Add getter for plugins' resource folder
Merge pull request #97 from zeuslightning125/master

Fixed existing javadoc, added missing @Overrides
Merge pull request #85 from jacklin213/documentation

Update JavaDocs, Game, World
Merge pull request #96 from jacklin213/patch-1

Update README.md, Forum Link
Fix typo and consistent capitalization.

Forums is not a proper noun.
Merge pull request #127 from drtshock/master

Fix typo and consistent capitalization.
It is not a requirement to squash commits in a PR

Now *please* stop with the "please squash" comments. Whoever pulls your PR can squash your commits.
Merge pull request #84 from Marenwynn/master

Add getter for plugins' data folder

Conflicts:
	src/main/java/org/spongepowered/api/plugin/PluginContainer.java
Use a static file header that is not declared as Javadocs.

Also make use of blank lines more liberally.
Reformat source code with IntelliJ IDEA preset

Some of this may be slightly off but it's better than it was
Merge pull request #152 from Kobata/style-reformat

Reformat source code with IntelliJ IDEA preset
Update README.md, add CONTRIBUTING.md

Signed-off-by: Steven Downer <grinch@outlook.com>
Add modifed google style checkstyle.xml

Commented-out things are features that require unreleased versions
of checkstyle.