Merge branch 'develop'
Merge branch 'develop'
Merge branch 'develop'
Fixed bug in the example criteria files (.py)

In the criteria example files provided, the mirscan function loops through the
list of candidates using 'for c in candidates:'. However in the past it was a
'for n in len(candidates): c = candidates[n]'. There was another usage for the
variable n in calling the appropriate member of the starts list. This change
caused an error where n was unavailable inside the function and the code
resorted to a global variable with the same name.
Candidate class now includes fold information

The class Candidate now stores the folds in a similar way to the mature strands.
The folds can be provided on initialisation though the parse_fam method
currently does not support parsing folds stored in .fam files. Folding can be
done on after initialisation through the compute_folds method which calls
RNAfold (other folding tools can be easily used) on all hairpins stored.
Merge branch 'hotfix/example_py_enumerate' into develop