Follow-up to Glacier pull request reviews

* updating Javadocs
* minor style changes
Add .mailmap
Up to 2.0.0-SNAPSHOT after the 1.8.0 release
Updating project and jclouds.version to 2.0.0-SNAPSHOT

Follow-up to 8fba1f2
JCLOUDS-457: Implementing getBlob without options

The missing getBlob implementation has been added.
Reset StringBuilder instead of creating new ones

This avoids unneeded garbage, especially during XML parsing.  Replaced
with:

find -name \*.java | xargs sed -i 's/^\( *[^ ]*\) = new StringBuilder();$/\1.setLength(0);/'
JCLOUDS-653: Address Guava 18 deprecations

Mostly renaming Objects.toStringHelper to MoreObjects.toStringHelper.
JCLOUDS-457: Extend javadoc and add README.md

Added more javadoc documentation. This covers the basics of the
provider.
Correct license headers
Remove maven-license-plugin

This never seemed to work and we will enforce license text via
Checkstyle instead.
Remove redundant modifiers from interfaces
Add missing @Override annotations
Fix glacier's pom structure.
JCLOUDS-40 unasync glacier.
JCLOUDS-40 Remove last reference to AsyncBlobStore in Glacier.
Fix poms so that modernizer doesn't fail on snapshot.
Revert "Fix poms so that modernizer doesn't fail on snapshot."

This reverts commit 70a3a4f86c82bf2e7b112de1599062141b46b120. The
snapshot repository has now been added to the jclouds-project POM.
See commit 79d4b48 to jclouds/jclouds.
JCLOUDS-40 unasync Fallback.
Revert "JCLOUDS-653: Address Guava 18 deprecations"

This reverts commit 710a7784eae58129a7796ac06c5e7b1d231ab4cf.