Merge pull request #62 from euanh/master

planex-build: Re-enable mock tmpfs plugin
Add mercurial support, change default mock config file

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Use a new mechanism for inserting info in the spec templates

Rather than directly controlling Version, we now put this into
a 'planex_version' define if it exists. Therefore a line like:

%define planex_version undefined

will turn into

%define planex_version 0.1.0+20+gabcdef

To get the previous behaviour, the Version line should then
look like this:

Version: %{planex_version}

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Remove mock dir - it wasn't being used and is wrong conceptually
Add planex demo

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Add some WIP documentation
Update demo.md
planex-fetch: Add a script to fetch a spec file's sources

Signed-off-by: Euan Harris <euan.harris@citrix.com>