Added support for .pointer-events.
Add native Trampoline support for unbounded recursion
Basic docs for trampolines
Hack to make imported names safe.

This fixes a bug where imported identifiers with reserved names were
not being changed during codegen.
Move splitDots and prevent a non-exhaustive pattern match warning
Change semantics of keepWhen/dropWhen.

They no longer propagate the right Signal when the left Signal
changes.
Uncomplicate keepWhen implementation
Remove old JS dropWhen/keepWhen
Simplify Trampoline datatype.
Update trampoline docs to new interface.
Merge branch 'master' into dev
Merge pull request #456 from maxsnew/trampoline

Trampoline
Get rid of dead code, cannot be called because of the type checker
attempt to make the documentation easier
Try to improve error messages in response to issue #479
Get rid of isClicked

It can be argued that everything should be derived from isDown and
position (the two real facts about the mouse), so maybe that is a
direction to go from here.
Merge pull request #439 from maxsnew/safeNames

Hack to make imported names safe.
Merge pull request #409 from maxsnew/keepWhen

Change semantics of keepWhen/dropWhen.
Add Date.fromTime function, based on PR #357
fix bad markdown performance