features2list: convert various input as features to a simple list
Description
Convert various input as features into a simple list, for input as a sequence in e.g. 
tokens_compound.Usage
features2list(features)
Arguments
features
the input features, one of: 
- character vector,
whose elements will be split on whitespace; 
- list of characters,
consisting of a list of token patterns, separated by white space; 
- tokens object; 
- dictionary object; 
- collocations object. 
 Value
an unnamed list of features, with each element of the list a
  character vector with the split sequence.