ENH: Add iter_regex and find_features

Fixes #612. Adds iter_regex to skbio._sequence.BiologicalSequence and
find_features to skbio._sequence.NucleotideSequence. Supported features are
currently purine_run and pyrimidine run, but more can be added by specifying
additional regular expressions.
Is this blocking or can we merge?

On Tue, Oct 7, 2014 at 4:06 PM, Yoshiki Vázquez Baeza <
notifications@github.com> wrote:

> In skbio/sequence/_sequence.py:
>
> > @@ -9,6 +9,7 @@
> >  from __future__ import absolute_import, division, print_function
> >  from future.utils.six import string_types
> >
> > +from re import compile as re_compile
>
> I think we don't have a standard but we suggest people use whatever the
> community uses. That being said I've seen both `from re import compile ...`.
> … <#148eca610ea2d0c1_>
> On (Oct-07-14|14:54), Evan Bolyen wrote: > @@ -9,6 +9,7 @@ > from
> __future__ import absolute_import, division, print_function > from
> future.utils.six import string_types > > +from re import compile as
> re_compile This might make more sense as `import re` then it becomes
> `re.compile`. Though I don't know if we have standards for this to indicate
> the use of one over the other. --- Reply to this email directly or view it
> on GitHub: https://github.com/biocore/scikit-bio/pull/613/files#r18552005
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/biocore/scikit-bio/pull/613/files#r18552712>.
>