Shows 'writeas' instead of generic 'command'

Found while going over new functionality (#6)

Keeps temporary post file around until a post successfully goes through.

Fixes the start command.
Saves the temporary file with .txt extension, so that Windows can correctly handle it.

Creates a new temporary file and posts whatever was written to it once
the user exits their editor.

TODO: don't lose work if something goes wrong in the posting process

Finishes issue #1

List local posts

Part of #4

Includes --id and --url flags for customizing the output

Uses the normal API for fetching posts, and appends .txt for current
hidden service API.

i.e., sans superfluous whitespace

So the executable will be named "writeas"

Plus only show post URL upon success

Includes:
- posting to hidden service
- a ton of code for {en,de}crypting that isn't used
- author: Write.as
- individual commands help

Includes posting ability using the current API utilized by the Android app at i.write.as.