add support for "scenarios", add more testing for paging with limit clause
code comment on multi exception init
scenarios, adjust exception handling

remove unneeded conditional logic and simplify --
now a "fatal" (non-deferrable) exception will still be raised as a MultiError
so that any earlier exceptions won't be hidden.
paging tests add more scenarios for paging with limit

now includes paging using =, and across multiple partitons with 'in'
Merge branch 'master' into scenarios_with_page_limit
adjust scenario to better trigger CASSANDRA-8408

reorder assertions to make it easier to see where scenarios fail
Merge pull request #122 from riptano/scenarios_with_page_limit

add support for "scenarios", add more testing for paging with limit