Madgui

bugfixes:

- fix undo feature not working because of using the wrong stack
- fix exception in Model.twiss when a table is specified

ORM analysis:

- share get_orm() implementation with orbit correction
- deduplications, several code improvements and simplifications
- use base_orbit to backtrack initial conditions
- add plot functions to the analysis script
- better output
- add ability to fit X and Y independently
- compacter ealign notation in undocumented spec file

Miscellaneous:

- require cpymad 1.0.0rc3
- fix multi grid view not being updated
- add units for K0
- update floor plan survey after twiss

Matching:

- group multiple matching constraints at the same element and position
into one statement
- specify weights only for the used quantities
- disable matching if the number of constraints is incorrect
- don't reset matching when deactivating the match mode

Element/param dialogs:

- fix condition for when globals are editable
- display element attribute names in title case again
- show leading part of variable names in lowercase
- make use of cpymad's ``inform`` and ``var_type``

TreeView:

- improve/refactor internal tableview API
- use tree view
- expand vectors in tree view
- expand variables occuring in expressions in GlobalsEdit/CommandEdit

Undo:

- support undoing simple .str files
- remove flawed accept/reject logic, i.e. "Cancel" buttons, leaving only
"Ok" buttons for now (the logic required to properly implement "Cancel"
is nontrivial, and the behaviour might still be confusing)
- move undo utils to their own module
- subclass QUndoStack
- never show empty macros (QUndoCommand.setObsolete)

Plotting:

- share loaded curves between all windows
- handle add_curve/del_curve in mainwindow
- "snapshot" now saves all available twiss data so that when changing
graphs, the snapshot for the other curves will be shown
- gracefully deal with missing data in user curves (showed exception very
loudly previously, showing debug message now)
- invert quadrupole focussing color codes in Y plot
- distinguish SBEND/KICKER sign by shifting the indicator position up/down
- smaller but more distinct indicators
- fade out "off-axis" kickers (e.g. HKICKER in Y plot)
- remove grid lines in Y direction
- fix missing element name in status bar
- update element markers on each draw

First reference point to define somewhat stable versions.

List of features:

- cpymad/pytao as simulation backends
- plots: alfa/beta/envelope/orbit; and the ones defined by tao
- integrated python shell (ipython/jupyter) not very useful as of yet:
limited exhibition of objects, no convenient APIs provided (plotting)
- log tab that shows madx/tao output
- tab that shows madx/tao commands
- display and edit box for beam parameters; initial conditions (i.e. twiss);
and element attributes (read-only so far)
- 2D floor plan
- matching (interactive + dialog)
- emittance (dialog)
- orbit alignment: 2-grid + N+optic methods

- Change Pyqtconsole v1.2.1

- fix drawing elements only once that occur multiple times in sequence
- add more documentation
- split twiss widget code from plotting module to allow using the plot
functions externally without importing GUI code

3D survey widget:
- fix bug in diffuse lighting direction calculations
- show thin elements as discs
- show more element types, colorful crowd
- fix not drawing the initial model
- scale number of points on circles with radius

- add "About python" menuitem
- fix bugs in ``Model.get_transfer_maps`` / ``Model.sectormap``
- collect multiple variable update commands into one RPC call
- add class for boxing generic values
- make ``Mainwindow.model`` a ``Boxed`` object!!
- remove ``Model.destroyed`` signal in favor of the more general
``Boxed.changed`` signal
- add ``envx``/``envy`` columns to ``get_elem_twiss``
- fix data export in "Read strengths"/"Write strengths" dialogs
- set "Ok" as default button in export widgets
- add menuitem for executing MAD-X files (i.e. CALL)
- remember folders separately for "load strengths" and "execute file" items