Added M2crypto.

Uses m2crypto to obtain signature algorith, size, issuer, serial,
common-name, subject-alternative-name, domains, valid_before, and
valid_after.

Fixed the slurp_exception region so an exception will now correctly
prevent the change watcher from identifying changes when an exception is
thrown.

Installing m2crypto can be a pain.  The following commands seem to work:
```sudo apt-get install swig; pip install m2crypto```.  It may be
required to run ```sudo apt-get install python-m2crypto```.
Removing re package and obtaining signature-algorithm in the same way as the other attributes
Adding IAM SSL checks for cert size and signing algorithm hash
Minor documentation fix
Merge branch 'feature/adding_m2crypto_to_iamssl' into develop