changed user#random_password

- new random password generation
- moved random_password test to spec
added SystemUser

- sometimes we need an existing user eg. for migrations
- it is possible to execute a block in the context of this SystemUser
fixed failing spec
fixed typo in comment of system_user.rb
more reliable spec for system user
added cukes for issue#edit

and issue#edit with preview
[OPF #812] fixes issue preview

- used jquery on instead of click for preview action
Open-sources timelines.

This represents the timelines plugin that was merged with the
OpenProject core and which had its history squashed. The timelines
plugin development was sponsored by;
Deutsche Telekom AG <opensource@telekom.de>

Requirements engineering and management were provided by;
Deutsche Telekom AG <opensource@telekom.de>
Finn GmbH <info@finn.de>

During the timelines development, the following authors have contributed
commits;
Martin Czuchra <m.czuchra@finn.de>
Nils Kenneweg <n.kenneweg@finn.de>
Romano Licker <r.licker@finn.de>
Gregor Schmidt <g.schmidt@finn.de>
Jens Ulferts <j.ulferts@finn.de>
Johannes Wollert <j.wollert@finn.de>

Quality Assurance was provided by;
Erdem Kabadayi <e.kabadayi@telekom.de>
Julia Pape <j.pape@finn.de>
Christian Rijke <c.rijke@finn.de>
Thomas Vogel <th.vogel@external.telekom.de>
Final merge with the original timelines plugin.

This includes all features that were added to timelines while
the merge with the core was being worked on.
Adds external timelines library names.

So they can be excluded when updating the copyright notice.
Updates copyright notice in timelines sources.
added cuke for calendar link

on project#show
white space fixes
[OPF #737] fix broken calendar link on

project#show
Merge pull request #166 from opf/feature/timelines

Open-sources timelines.
Fixes database index names on postgres.

According to 4.1.1. Identifiers and Key Words [1] of the PostgreSQL
9.2.4 Documentation, NAMEDATALEN is 64 so the maximum identifier length
is 63 bytes.

[1] http://www.postgresql.org/docs/current/interactive/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS
Merge pull request #167 from opf/fix/postgres

Fixes database index on postgres.
Merge pull request #165 from opf/feature/rails3_fix_calendar_link_on_project_show

rails3 fix calendar link on project show
Merge pull request #162 from opf/feature/rails3_fix_issue_preview

rails3 fix issue preview
Merge pull request #150 from opf/features/rails3_add_system_user

Features/rails3 add system user