refactor: single implicit import of pyTMD tools (#130)
refactor: reorganization of tide model readers under io (#132)
refactor: placed interpolation routines into new module (#141)
refactor: move model class to io
feat: add constants class for ellipsoidal and gravitational parameters (#135)
feat: functions to read and interpolate from all constituents (#137)
feat: new functions to output ATLAS, FES and GOT netCDF4 files (#139)
feat: output variables for some standard epochs used within tide programs
feat: update forecast notebook with dynamic plotting
fix: copy input coordinates within read functions so they are not transformed
docs: update documentation for new structure
docs: standardized citation format throughout docstrings
docs: add release notes for all prior public releases
docs: add new pyTMD logo
test: read header from OPT test file and compare more variables
test: add tests for io methods