Add SOD523 5.1V zener diode
Fix #2492: Change the repolist function to use gerrit

Our own hosted repolist hasn't been being updated since we moved
to gerrit, and frankly there's little point in fixing that when we
can just have gerrit tell us the list of projects anyway.

Change-Id: I1f1a3adbae50d9737e9b415a9a49a261601a30a3
Add ability to query using serial number

Using `serial:<thing>`.
Merge branch 'master' of ssh://srobo.org:29418/tools
Add 14mm M3 hex standoff
Add a ticket creation helper which vaildates metadata.

Change-Id: Ia23b2df00be7efe3ba8540ac8df79ec283e263d0
Introduce constants for defaults.

Change-Id: I809349c49e4b49cf69c5eb1fbff32091198b3f74
Extract building the dependencies list to a helper

This makes it possible to create such a list from a collection of
dependency numbers outside this class.

Change-Id: Ia36dd30bee2757aa223d198fbafac3cdc4f4a11e
Add a script which imports a repo of tasks into trac.

Said repo contains a collection of yaml files, each representing
a single task which will become a ticket. This builds on our existing
trac support, so includes dependency resolution before addition.

Each task can be uniquely referred to through use of its task name. This
is the path to the file relative to the root of the repo and without the
'.yaml' extension. For example: 'comp/main'.

Attributes on the tickets are represented by top level keys within the files,
with the addition of a 'dependencies' key.
This allows the listing of task dependencies in the following ways:
 * By the name of the task
 * By a glob on the name of some tasks
 * By existing ticket number within the target trac instance, prefixed
   with an underscore rather than a hash so that it doesn't get treated
   as a comment by the yaml loader. For example: '_545'.

Change-Id: I9e9808a506606fdb52f4512b76d0dec1de0d547e