Merge pull request #3 from lddubeau/develop

Merge the latest state of development.
Version bump for 0.5.
Merge branch 'release/0.5.0' into develop
Dropped the anonymous function method of creating classes.
Added splitAt.
Added firstDescendantOrSelf.
Added key.js and its tests.
The key constants used by wed.
Added input_trigger and its tests.
Added documentation.
Generic mode now uses _getTransformationRegistry to allow derived classes to provide their own registries.
Allow InputTrigger to be initialized through the construction of the decorators. The bit of code that was moved was called too early.
Fix the copy code. Determining the location of text nodes that have been deleted is difficult so don't try to be clever.
Added _syncDisplay for debugging and testing.
Added fireTransformation.
Added toTreeNode.
Bugfix: don't let a backspace even propagate if at the beginning of a text node.
Use key_constants instead of ad hoc tests.
Merge branch 'develop' of https://github.com/mangalam-research/wed into develop
Removed an unnecessary assertion that happened to fail on Firefox.