upgrade DataTables from 1.9.4 to 0.10.2; closes #487
fix a bug when the number of rows of data to show is zero

all(logical(0)) == TRUE!
tweaking the bootstrap style copied from DataTables:

1. sorted columns have different colors;
2. correct position of the processing info;
3. override the width of text input (search fields), otherwise they will be too wide (206px defined in bootstrap.min.css);
the names of keys and values are useless
support [] in query strings like $_GET in PHP, because server-side DataTables 1.10 passes parameters as arrays

e.g. columns[0][search][value]=foo&columns[1][search][value]=bar

we need list(columns = list(`0` = list(search = list(value = 'foo')), `1` = ...)
new option names for DataTables from Hungarian to camelCase notations
tweak doc and roxygenize
get rid of the ugly trick eval(parse()), and use a plain loop to create a nested list
background color for selected rows
add instructions for upgrading from DataTables 1.9 to 1.10
need a newer version of htmltools due to 5f4c8cf176f12e58b86d4b216a8d7bc0b9849b93 and the bug rstudio/htmltools#7
Merge pull request #558 from yihui/feature/datatables1.10

DataTables 1.10.2
use the latest version of htmltools