Rework the skeleton and flesh out a good pattern for the API

#### Details

* Reworks the base skeleton
  * Uses Travis-CI for CI
  * Uses RTD for documentation hosting
  * Moves tests out of the package
  * Switches to utilizing py.test for cleaner / simpler testing
  * Adds some basic project level docs
  * Cleans up the packaging
* Fleshes out the API foundation
  * ``symantecssl.Symantec`` acts as the central "entrypoint".
  * Authentication is handled transparently through the use of ``symantecssl.auth.SymantecAuth``.
  * ``symantecssl.models.BaseModel`` provides sane defaults for as much behavior as possible.
  * Ensures that TLS1.1+ is never used due to the symantec API endpoints being severely broken and unable to properly negotiate a TLS 1.1+ connection although they advertise support for it.
* Creates the QuickOrder API Endpoint
  * Uses enums to enable easier specification of parameters where the values are of a finite set.
    * Still supports passing the "raw" value documented in the Symantec API docs
  * Handles the response from the API in order to detect success/fail
    * On Failure, raises a ``symantecssl.exceptions.SymantecValueError`` which contains more information about what exactly failed.
    * On success, returns a dictionary listing the partnerorderid and the geotrustorderid

#### Thoughts

I'm not entirely happy about the ``Symantec().submit()`` function, however I'm unable to think of a better name, and simply omitting it and using ``__call__`` instead looks worse to me than not using ``submit``. 

I'm also not entirely happy with the response handling code, however until we see what the responses tend to end up looking like it's going to be hard to write generic handlers for them. Hopefully there will be a common pattern that we can abstract and remove the need to write additional boilerplate.

#### Example

```python
from symantecssl import Symantec, order


customer_order = order.Order(
    partnercode="...",
    productcode=order.ProductCode.SSL123,
    organizationname="MyOrg",
    addressline1="5000 Walzem",
    city="San Antonio",
    region="TX",
    postalcode="78218",
    country="US",
    organizationphone="2103124000",
    validityperiod=order.ValidityPeriod.OneYear,
    serverCount="1",
    webservertype=order.WebServer.ApacheOpenSSL,
    admincontactfirstname="John",
    admincontactlastname="Doe",
    admincontactphone="2103122400",
    admincontactemail="someone@email.com",
    admincontacttitle="Caesar",
    admincontactaddressline1="123 Road",
    admincontactcity="San Antonio",
    admincontactregion="TX",
    admincontactpostalcode="78218",
    admincontactcountry="US",
    techsameasadmin=True,
    billsameastech=True,
    approveremail="admin@testingsymantecssl.com",
    csr="""
-----BEGIN CERTIFICATE REQUEST-----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-----END CERTIFICATE REQUEST-----
""",
)

api_url = "https://test-api.geotrust.com/webtrust/partner"

api = Symantec("...", "...", url=api_url)
d = api.submit(customer_order)

print(d)  # {'PartnerOrderID': '...', 'GeoTrustOrderID': '...'}
```