modify pager widget to handle boundary conditions; now takes a Dataset i...

modify pager widget to handle boundary conditions

now takes a Dataset instead of a Query so that it has access to the record count 

add tests

some examples (tested on http://reclinejs.com/demos/multiview/)
- pager inputs show 0-100 instead of more user-friendly 1-99 (or 1-6 since there are only 6 records)
- pager shows to 100 even though there are only 6 records (now shows 1-6)
- to value is exclusive, so clicking next from 0-6 shows 6-12.  It's not immediately obvious where record #6 gets displayed (now clicking next increments the to value)
- clicking next shows 100-200 in pager, and no results (now does nothing)