implemented meta+k for the ui

will wrap the content and insert a link at the current position
introduced Keys.shortcutHandler wich helps to implement keyboard shortcuts
refactored typing.js to also use Keys.shortcutHandler
Refactoring event pipe to only process editable events
Update boundaries when clicking outside of ui and editable
Put boundaries in event.selection.boundaries
Obsolete newContext()
context -> selection
Streamling events some more
refactored from aloha-bootstrap-ui to aloha-ui

aloha-ui can be used with plain html - bootstrap is not a necessity
refactored .aloha-toolbar to .aloha-ui
Removed jQuery from the ui code, still work in progress

Link UI ist not working properly
Correct doubleclick event
Work in progress