This pull request is to extend the GET /api/jobs request/response.

1.) If the submitted api key is an admin's key AND the request has an included data_range_min
    or date_range_max value, the response will include jobs from all galaxy users.
2.) The response for (1) is extended to include
        a) external_id
        b) galaxy job id
        c) user email
3.) All users can submit a date range filter.
4.) Existing calls are unaffected by the change:
https://galaxy-ng.msi.umn.edu/api/jobs?key=xxxxxxxxxxxxxxxxxxxxxxx
[
    {
        "create_time": "2014-12-01T19:23:37.270768",
        "exit_code": 0,
        "id": "cffdbbf7257b6526",
        "model_class": "Job",
        "state": "ok",
        "tool_id": "upload1",
        "update_time": "2014-12-01T19:24:24.608105"
    }
]

5.) Extended admin request:
https://galaxy-ng.msi.umn.edu/api/jobs?date_range_min=2014-11-01?&key=xxxxxADMIN_KEYxxxxxxxxxx
...
{
        "create_time": "2014-11-11T15:59:19.909902",
        "exit_code": 0,
        "external_id": "31325.nokomis0015.msi.umn.edu",
        "id": "2003774561413b68",
        "job_id": 3733,
        "model_class": "Job",
        "state": "ok",
        "tool_id": "testtoolshed.g2.bx.psu.edu/repos/tmcgowan/fastqc/fastqc/0.60",
        "update_time": "2014-11-11T16:00:10.872804",
        "user_email": "mcgo0092+msistaff@msi.umn.edu"
    },
    {
        "create_time": "2014-11-10T15:15:31.801047",
        "exit_code": 0,
        "external_id": "30299.nokomis0015.msi.umn.edu",
        "id": "e330bc56cb5095a7",
        "job_id": 3732,
        "model_class": "Job",
        "state": "ok",
        "tool_id": "testtoolshed.g2.bx.psu.edu/repos/jjohnson/snpeff/snpEff/4.0.1",
        "update_time": "2014-11-10T15:16:31.996148",
        "user_email": "jj+support@msi.umn.edu"
    }
    ...
Edits based on reviewer comments. Removed redundant email query, removed job_id from response. Added user_details as param.
Merge pull request #610.
PEP-8 fix for api/jobs.py.
Increase consistency between job index and show.
Add tests for new date range and history filtering as well as to ensure only admins get to see external_id and command_line and that users cannot see each other's jobs.

Always allow admins to views all jobs on index (instead of only when user_details is specified) and show. Add user_email and external_id to show (for admins) to bring it inline with index and add command_line to index (for admins) to bring it in line with show.

Show still allow more details including job standard error and output as well as job metrics.