build: Switch to argparse for argument parsing

Signed-off-by: Euan Harris <euan.harris@citrix.com>
build: Add --external-dependencies flag

Signed-off-by: Euan Harris <euan.harris@citrix.com>
XenBuilder integration: Include external dependencies in cache hashes

Signed-off-by: Euan Harris <euan.harris@citrix.com>
Fix the unit tests

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Increase coverage of sources.py tests

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Remove test_install.py and use euanh's suggestions on PR#67

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Merge pull request #74 from jonludlam/fix-tests

Fix tests
Merge pull request #73 from euanh/external-dependencies

Include external dependencies when calculating package hashes for caching
Add back in the ability to use a github mirror directory

Also bring the test coverage of sources.py up to 100%!

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Merge pull request #75 from jonludlam/reinstate-github-mirrors

Add back in the ability to use a github mirror directory