Added new Config value for libraries

This config value specifies the paths to required Android
Library projects (relative to the project base dir). When
present, it supercedes the libraries from project.properties.

Also added a few constants in AndroidManifest.java to replace
hard-coded strings.
Fixed NPE on StrictMode.setVmPolicy
Implement Theme.applyStyle() correctly.

Existing implementation only sets (and overrides) previous theme styles. Correct behaviour should overlay styles of the original Theme replacing original attributes conditionally when "force" == true.
Add overlayed styles to the end of the list not the beginning, the ones added later are the ones that are applied last.
Initialize attr array as empty array when passed in as null.
Only look up style resource if it could be resolved.
Rework how overlayed styles are applied in Robolectric.

ShadowAssetManager should keep a list of overlayed styles, but rather than trying to process them in the theme we should do so in ShadowResources since we need to resolve each attribute and any possible references through indirection at this point.
Add support for mipmaps in layouts.
Merge branch 'master' of https://github.com/robolectric/robolectric into support_mipmap_resources
Fix incorrect assertion in the test. The change in this PR inadvertantly fixed a bug whereby invalid resources were being added to the map.
Merge branch 'master' of https://github.com/robolectric/robolectric into fix_theme_apply_style

Conflicts:
	src/test/java/org/robolectric/R.java
	src/test/java/org/robolectric/shadows/ResourcesTest.java
Fix merges from regenerated R.java file.
Removed IDEA generated headers
Merge pull request #1263 from karlicoss/strict-mode

Fixed NPE on StrictMode.setVmPolicy.
Merge pull request #1204 from awrichar/libraries

Added new Config value for libraries.
Merge pull request #1277 from jongerrish/fix_theme_apply_style

Implement Theme.applyStyle() correctly.
Merge pull request #1282 from jongerrish/support_mipmap_resources

Add support for mipmaps in layouts.
Implement Time.switchTimezone.

Closes #1276.
ShadowAssetManager dereferences attrs better

ShadowAssetManager now looks in the full style tree (children and
themes) while dereferencing parent styles.

In order, ShadowAssetManager will search:
 - All known children in this style path
 - The Theme Style
 - The ResourceLoader

Improves the logging information when a parent style can't be found.