Schemdraw

- Added Digital Timing Diagram elements
- Added Table and Kmap elements
- Added Arc2, Arc3, ArcN, ArcZ, ArcLoop elements, useful for state machine diagrams
- Added drop method to Element class to specify where to leave the drawing position
- Added move_from method to Drawing class to move relative to another element anchor
- Added more anchors to all flowchart elements
- Improved layout of flowchart elements. **May affect layout of some existing flowchart diagrams.**
- Added SegmentBezier for creating elements with curves
- Deprecated SegmentArrow in favor of Segment with arrow parameter

- Fixed Arrow and LineDot element placement when placed with anchor
- Fixed copy/pickle of Element class
- Fixed importing * from schemdraw.elements

- Fixed placing elements by anchor when anchors were defined using a tuple rather than Point
- SVG backend adds option for SVG1.x format for better compatibility with SVG renderers
- Restore compabitliiby with Python 3.7 via conditional import of typing_extensions.

- Added options to place labels inside Mixer elements
- Fixed arrowhead overshoot
- Fixed get_imagedata function
- Update pip install to include optional dependencies
- Added ziamath optional dependency for rendering math in SVG backend
- Added LoopArrow as superclass of LoopCurrent, for placing a loop anywhere

- Fixed missing module in setup.py.

- Added optional SVG backend for drawing directly to an SVG image
- Implemented method-chaining "fluent" interface for building elements
- Added `elements.style` method for setting U.S. or European/IEC resistor style
- Added parameter for drawing schematic on existing matplotlib axis
- Added string parser for creating logic diagrams from expressions like "A or B"
- Fixed zooming of arc segments
- Added type annotations
- Added `Drawing.move` method for moving cursor by dx and dy.
- Drawing class implements += operator, so elements can be added by `Drawing += Element()`
- Removed dependency on Numpy
- Added Drawing.interactive` to allow element-by-element drawing with Matplotlib's plt.ion().
- Now requires Python 3.8+

- New Elements:
- CPE (Constant Phase Element)
- Varactor
- FuseIEEE
- FuseIEC
- SwitchRotary
- SwitchReed
- Jack
- Plug
- Ic555
- IcDIP
- SevenSegment
- Outlet Elements

- Deprecations:
- `Element.add_label` is deprecated (use `Element.label`)
- `Drawing.loopI` is deprecated (add a `LoopCurrent` element)
- `Drawing.labelI` is deprecated (add a `CurrentLabel` element)
- `Drawing.labelI_inline` is deprecated (add a `CurrentLabelInline` element)