engine/views:

Abstracted `_get_base_url`.
engine/views:

Reorganized util functions.
engine/views:

Added `calc_hazard_results` and `calc_risk_results` views.
engine/tests:

Abstracted BaseViewTestCase.
engine/tests:

Refactored a coupe of tests to check the dict form of json results,
rather than the string representation. This makes the tests a bit
more reliable.
engine/tests:

Fixed a comment typo.
engine/tests:

Added tests for `calc_hazard_results` and `calc_risk_results`.
engine/tests:

Added some tests specifically for `_get_base_url`.
engine/v1/calc_urls:

Corrected a comment.
engine/v1/calc_urls:

Added url mapping for the calc results views.
engine/v1/calc_urls:

Minor correct to url mapping regexes.
Merge pull request #4 from larsbutler/list-calc-results

"List calc results" views

[r=daniviga] [f=1205275]