Write release notes for 0.5.3

Merge pull request #11 from vanitery/patch-1

Update process_file.py

rst formatting changelog

add all fit functions to init

Add the new fit functions to the API docs

Update key for conda env in rtd config

don't track _build folder for docs

Update docs to use new readthedocs config file format; add lmfit to docs build deps since a few docstrigns pull from lmfit

Merge pull request #9 from FaustinCarter/patch-v0.5.2

Switch from lmfit.models.COMMON_DOC to lmfit.models.COMMON_INIT_DOC

Merge pull request #7 from FaustinCarter/patch-v0.5.1

Version bump and release notes

Lingering bug introduced during offset parameter name change

Numpify array before trying numpy things with it