- Replace CHAR_BITS and M_PI to C++ replacements
- Remove void function returns
- move rvalue references / prefect forward universal references
- move type_traits to C++17 '_v' suffixes
- include all includes to c++
- Remove nested ? : ternary operators
- Remove implicit inlines
- Make all enum base to uint8_t
- Remove some unnecessary namespace prefix
- Change enable_if to requires
- std::ignore some argument
- header guard to canvas.h

# Conflicts:
#	src/base/geom/circle.cpp
#	src/base/geom/circle.h
#	src/base/geom/rect.cpp
#	src/base/geom/triangle.cpp