function_logic

I need a function for each possible output. 
It seems good practice to use the googlesheets pacakge naming system

bt_read.log
bt_read.schedule
bt_read.stones

etc. 

To avoid name clashes. 

All output should be dataframes. 

Ideally this could feed into a general read.bayestraits function, with an argument for which type to use. 

I need to identify how the output files differ based on the model run. But I think they are pretty generic. 
Particulary in the case of continuous models. 

Added bonus:
	Make an attributes function which takes the top settings from the header of each file and adds them
	as attributes to the data frame output
	
Writing Bayestraits files would also be a useful function that I already have

bt_write.bayestraits
	With data object, tree object inputs
		Also taxa column & value column, chaning NAs etc. 
		I have mostly done this I think.