user: fix password info JSON encoding to survive round trips

PasswordInfos are marshaled when storing them in the database as
part of the local connector. However, the custom unmarsheler
defined could not unmarshal the standard marshling of this struct.

Add a struct tag to the Password field to correct this.

Closes #332

move to sqlite3 for --no-db mode and tests

Documentation: update roadmap with issue and PR numbers

Closes #299

*: add go 1.6 to CI

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

go-sqlite3 takes a long time to compile, so it's very important
to cache a build rather than re-compile every time.

Use go install instead of go build in the build script to cache
all packages. Print a warning in the test script if cached packages
are not found.

The DB implementation expects secrets to be base64 encoded blobs.
Because of this a bunch of tests broke moving to sqlite.

A lot of this commit is fixing those tests.

Move manager to it's own package so it can import db. Move all
references to the in memory session repos to use sqlite3.

Adjust logic and remove panics from functional tests.

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