added textile hooks
added textile patterns to all_patterns
added pat_textile function
added textile out.format to knit fn
added rtextile option to auto_out_name
fixes #628: new parameter precious for spin(), default is to remove intermediate files if knitting and input is a file
update NEWS
update NEWS
Merge pull request #632 from krlmlr/628-spin-precious

"precious" parameter for spin()
Merge pull request #622 from knokknok/master

new 'asis' engine that will output the code without trying to process it
Merge pull request #623 from richierocks/master

Textile support, 2nd attempt
tweak the illustration of latex figure environment
slight tweaks after #632
roxygenize for #632
make sure the output format is latex when we call render_latex()
no need to use do.call() -- just get the function from namespace and call it
I have an old bug here: knit2pdf() should be called when nosrc=TRUE (i.e. the text argument was not used), but I wrote !nosrc instead

it is safer to check is.null(outsrc) than nosrc=TRUE, so I did it, and reformatted the code a bit

besides, #632 is buggy: the variable out may not be created, so I moved it out of if () {}
tweak #622: the code can be as simple as this; no need to pass to engine_output()

I changed the option eval to echo
add the missing comma for #623
make the base url work for textile, i.e. opts_knit$get('base.url') #623