* Adds the ability for destination plugins to be sub-classed from ExportDestination. These plugins have the extra option of specifying an export plugin before the destination receives the data. Closes#807.
* fixing tests
Mostly typos, grammar errors and inconsistent indentation in code
examples.
Some errors detected using Topy (https://github.com/intgr/topy), all
changes verified by hand.
Curtis Castrapel
kevgliss
Marti Raudsepp