Schemdraw

- Added function for drawing multiplexers/demultiplexers
- Updates to labelI() method to allow reversing arrow and changing length
- Add CSS to documentation
- New elements:
- PHOTODIODE
- NFET4
- PFET4
- VSS
- VDD

- Documentation updates
- New elements:
- Transformer
- Josephson Junction (JJ)

- Fixed anchor names when element overwrites base anchor, such as BJT_PNP.
- Added showplot keyword to draw() for non-interactive mode.
- Added 2-collector BJT.
- Documentation: added gallery of schematics.

- Added default line width argument to drawing() class. Default width is now 1.5.
- Converted documentation to use all vector-based images
- Added XKCD-mode example
- New elements:
- BATTERY
- BAT_CELL
- SPEAKER
- BUTTON
- BUTTON_NC
- XTAL
- MEMRISTOR,
- SCHOTTKY
- ZENER
- LED2

- Add function to group several elements into one
- Add blackbox() function to generate box elements with arbitrary inputs
- Allow element definition to specify label alignment
- Added linestyle to element kwargs and definition
- New elements:
- LED
- OPAMP_NOSIGN
- GAP_LABEL
- ELLIPSIS

- Added logic gate elements
- Added transparent and dpi options to save() function
- Fixed issues with zooming and rotating elements with arcs
- LaTeX typesetting uses sans-serif, regular fonts for consistency