making plugin installation and docs support a little more robust
updated remote test script to have docs pulled even if there are test failures
Merge pull request #1532 from naylor-b/plugin_docs

update to make 'plugin docs' more robust
fixing a bug
Merge pull request #1533 from JustinSGray/expr_deriv_fix

Bug in exprs when one var name was a sub-set of another var name.
fixed bug in initialize_residual when input value is not a tuple
added a test
fixed test to run as part of a group of unit tests (set_as_top issue)
Merge pull request #1534 from naylor-b/single_letter

fixed bug in initialize_residual that occurred when inputs passed to check_gradient are not tuples.
conflict