This allows client to view authenticated user's information.

Ref T734

This allows applications to verify the environment they're interacting
with.

Support Markdown endpoint

from 2-dev

This explains what happened, instead of telling the user what to do.

This reverts commit 8463946e2d6b211208c04eb6832f155865d12de3, reversing
changes made to 8cf5d50560.

include collection and id in postparams

this changes the JSON tags to include both the ID and Collection
in PostParams. Both will be omitted when empty to maintain any unknown
backwards compatibility.

this changes tests to only use the dev client as all code is shared
between that and the write.as client, just the host changes.

also updated post tests to round trip and test over sub tests

tests were failing on expected write.as blog title
previously the title was 'write.as' and it is now 'write.as blog'

also removed test case ExampleClient_GetCollection as was a duplicate of
TestGetCollection

this adds a client method to retrieve a collection post along with basic
tests - phabricator task T588

collection: Add support for deletion

This reverts commit 1d34eede72.

Support modules

style: Run goimports on everything

for creating or updating posts.

for creating a new collection.

Support Go Modules

Rather than accepting a naked string, accept a DeleteCollectionParams
struct so that new optional parameters can be added in the future
without breaking the API.

This adds support for deleting collections.

Resolves #1.

Similar to writeas/writeas-cli#22, this change runs goimports on all
files and changes the recommendation in the Contributing section to do
the same.

Add NewClientWith constructor

This adds a new constructor to build Clients which operates on a Config
struct rather than positional parameters. This will enable adding new
parameters in the future without breaking the API.

To begin with, this introduces a new URL parameter that wasn't
previously available. An example of another parameter that could be
added in the future is the timeout (to override the default timeout).

Existing constructors have been transitioned to the new one because it
implements a superset of their functionality.

Minor note: The Tor constructor wasn't respecting the default timeout
but with this version, it does.

Resolves #8

Fixes bug introduced when we moved `Token` into the func's parameters,
out of PostParams.

Moves the ID and token params out of PostParams and into the func's
parameters. A currently-unused `collection` parameter is left in for the
future, when the backend supports updating and deleting collection posts
via slug, not post ID.

Previously, they all said the same thing