connector_ldap: Make constants for default values, simplify logic

Get DN from entry, not entryDN attribute

Not all LDAP servers have entryDN available as an attribute. Reading up on
https://tools.ietf.org/html/rfc5020 tells me that entryDN is intended for
making the DN available for attribute value assertions. Thus it is not
mandatory for a LDAP server to make it available as an retrievable
attribute.

The DN is always a part of the entry returned in a search result, just use
it.

Fixes #314

connector: add LDAP connector

Authentication is performed by binding to the configured LDAP server using
the user supplied credentials. Successfull bind equals authenticated user.

Optionally the connector can be configured to search before authentication.
The entryDN found will be used to bind to the LDAP server.

This feature must be enabled to get supplementary information from the
directory (ID, Name, Email). This feature can also be used to limit access
to the service.

Example use case: Allow your users to log in with e-mail address instead of
the identification string in your DNs (typically username).

To make re-use of HTTP form handling code from the Local connector possible:
- Implemented IdentityProvider interface
- Moved the re-used functions to login_local.go

Fixes #119

README: add note about roadmap and google group

Closes #297

cmd: add version to command worker and overlord, print go version

add generated documentation for APIs

add dynamic client registration

Documentation: move proposals to their own sub directory

 admin: tests do not compile (Fixes #257)

includes admin in the test script and fix the api_test compile errors

Fixes #257

worker start command missing registration and emailer config.

worker start command missing registration and emailer config. exported as env variables like other properties.

Documentation: fix --db-url flag

As was noted in #293 --db-url must take two slashs, not one.

Fixed db-url flag in standup-db.sh

Documentation: add section about using godeps

Change status code used for redirects from StatusTemporaryRedirect (3…

HTTP code 307 aka. StatusTemporaryRedirect is used throughout the
project. However, the endpoints redirected to explicitly expects
the client to make a GET request.

If a HTTP client issues a POST request to a server and receives a
HTTP 307 redirect, it forwards the POST request to the new URL.

When using 302 the HTTP client will issue a GET request.

Fixes #287

server: fix reset password test

travis: quote cwd build-docker-push script

TestResetPasswordHandler depended on makeToken begin called twice
during the initialization of a single test case and later assuming
the result would match. Because the token has a timestamp accurate
to the second, occasionally the timestamps would be slightly off
within a single test case and cause the test to fail.

Adding a sleep statement to makeToken would cause the test to fail
reliably.

Define a single token for each test case outside of the struct
initializer so test cases compare the same token.

Closes #274

Additionally remove logging statements that dump entire HTML pages.

*: move user API auth to middleware and fix return status

Move client authentication into its own middleware and provide
differentiation between HTTP requests that do not provide
credentials (401) and requests that authenticate as a non-admin
user (403).

Closes #152

travis: Change from after_success script to travis deploy

db: log ignored base64 decode error

*: allow dexctl set-connector-configs to read from stdin

Closes #276

Closes #270