refactoring for notebook versioning
more refactoring for notebook versioning
support sending NULL to rserve
missed one param refactoring for version support
preliminary support for notebook versioning

quite a few bugs n tweaks to go
refactor editor classward; get history ui basically working

add_history nodes adds a set amount or restarts to a chosen num
create private members (but not use of "that" yet)
consequently remove a lot of function parameters
consolidate id creation
build up config incrementally (to repair incomplete user config files)
try to make variable names somewhat more descriptive
weird last_chance callback in update_tree :-/

could still probably use d3 or mvc ;-)
update jqtree to 0.17
load history through curr version if loading an old version

find index of old version in history and display a bit more
add callback for add_history in order to open tree node and select
they fixed a glitch in jqTree
hack in access to jqTree selectNode's must_toggle parameter
rename private variables to underscore suffix
ellipsis for more history

disable history button when showing prior version
create tree widget only after we have all the data
whitespace
refactoring around fork/revert

fork and revert on same link
make shell classier
turn fork into revert for own notebooks

(revert and fork from prior versions still not implemented)
correct error message
revert and fork from prior version

revert calculates the changes from HEAD to an early version and applies them
fork from prior version first forks (another user's) notebook and then reverts
also:
- keep version list open when clicking on HEAD
- support for versions in URL
- some bug fixes for view.html/view.js

this introduces some extra inefficiencies (#54) and code is a bit messy (#55)
Notebook history: show history, revert, and fork from prior version