[maven-release-plugin] prepare release adam-parent-0.6.0
[maven-release-plugin] prepare for next development iteration
Added the "tags" command, and parsing for BAM attributes.

Added code (in Attribute and AttributeUtils) to parse attributes -- the optional fields at the end of a SAM record -- from the string which is stored in the ADAMRecord.

Updated the adam-cli project with a command, 'tags', that reads an ADAMRecord set and prints the total set of tags found in the set, along with the number of times each tag appears.
Renamed Attributes->Tags.

Attributes are key=value, tags are BAM-style key:type:value, both are tab-separated.
We expect to see tags in the SAM/BAM file, and attributes in the ADAM files.
Added the -counts option to PrintTags.