Renamed the invert() function in iter.rs to flip().
Also renamed the Invert<T> type to Flip<T>.
Some related code comments changed. Documentation that I could find has
been updated, and all the instances I could locate where the
function/type were called have been updated as well.
The `print!` and `println!` macros are now the preferred method of printing, and so there is no reason to export the `stdio` functions in the prelude. The functions have also been replaced by their macro counterparts in the tutorial and other documentation so that newcomers don't get confused about what they should be using.
Ensure configure creates doc/guides directory
Fix configure makefile and tests
Remove old guides dir and configure option, convert testing to guide
Remove ignored files
Fix submodule issue
prepend dir in makefile so that bor knows how to build the docs
S to uppercase
