bitbake: layerindexlib: Initial layer index processing module implementation

The layer index module is expected to be used by various parts of the system
in order to access a layerindex-web (such as layers.openembedded.org) and
perform basic processing on the information, such as dependency scanning.

Along with the layerindex implementation are associated tests.  The tests
properly honor BB_SKIP_NETTESTS='yes' to prevent test failures.

Tests Implemented:
   - Branch, LayerItem, LayerBranch, LayerDependency, Recipe, Machine and
      Distro objects
   - LayerIndex setup using the layers.openembedded.org restapi
   - LayerIndex storing and retrieving from a file
   - LayerIndex verify dependency resolution ordering
   - LayerIndex setup using simulated cooker data

(Bitbake rev: fd0ee6c10dbb5592731e56f4c592fe687682a3e6)

Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/layerindexlib/tests/testdata/layer3/conf/layer.conf

@@ -0,0 +1,19 @@
+# We might have a conf and classes directory, append to BBPATH
+BBPATH .= ":${LAYERDIR}"
+
+# We have recipes directories, add to BBFILES
+BBFILES += "${LAYERDIR}/recipes*/*/*.bb ${LAYERDIR}/recipes*/*/*.bbappend"
+
+BBFILE_COLLECTIONS += "meta-python"
+BBFILE_PATTERN_meta-python := "^${LAYERDIR}/"
+BBFILE_PRIORITY_meta-python = "7"
+
+# This should only be incremented on significant changes that will
+# cause compatibility issues with other layers
+LAYERVERSION_meta-python = "1"
+
+LAYERDEPENDS_meta-python = "core openembedded-layer"
+
+LAYERSERIES_COMPAT_meta-python = "sumo"
+
+LICENSE_PATH += "${LAYERDIR}/licenses"