bugfix rollup release

Merge pull request #210 from TimmyLiu/master

merge develop branch into master branch. bump the version number to 2.10

Merge pull request #151 from guacamoleo/master

promoting develop to master

Merge pull request #119 from TimmyLiu/master

merge develop branch into master branch. bump the version number to 2.6

Merge pull request #80 from TimmyLiu/master

merge develop branch into master branch

v2.2 is a bugfix release, incorporating all bugfixes in the develop

branch.  This corresponds approximately to the state of the code
when ACML 6 shipped.

Changing version number to 2.0