Stable build v3.1.5

feature added:

1. add commonjs type definition file generation, thanks @grainrigi
2. add 'types' to package.json 'exports' root, thanks @jeremybanka

Issues addressed:

1. fix #165: check and make buffer before parse
2. fix #373: handle bad encoding expcetion by start page rendering after page operator list is resolved
3. fix #306: infinite loop of invalid stram
4. fix #369: handle object value for field's rectangle coordinates
5. other maintenance, eslint, tsconfig, dependency version bumps, etc.