Merge pull request #165 from sphereio/customers

Customers
Make all enum constants uppercase.
Merge pull request #173 from sphereio/orders

Orders
Setting version to 1.0.0-M8
Setting version to 1.0.0-M9-SNAPSHOT
Update version in documentation to 1.0.0-M8.
Document AbsoluteProductDiscount.
Document AddCustomLineItem and make quantity a long instead of int.
Start ConstructionDocumentation.
Document object creation.
Merge query documentation into one. Close #181
Document known issues. #183
Fix Javadoc.
Remove flaky test.
Merge pull request #186 from sphereio/documentation-improvements

Documentation improvements
Merge branch 'master' into request-response-refactoring

Conflicts:
	src/main/java/io/sphere/sdk/meta/ReleaseNotes.java