Made all parameters for fitting functions single elements, rather than arrays
Updated tests with higher-redshift data
remove ds_store
add basic_usage doc
Added filters.py for different filter function models
fixed some bugs in filters
Merge branch 'different_windows' into wdm_models

* different_windows:
  fixed some bugs in filters
  Added filters.py for different filter function models
  add basic_usage doc
  remove ds_store
  Updated tests with higher-redshift data
  Made all parameters for fitting functions single elements, rather than arrays
Fixed bug in updating filter, and added Viel05 WDM model