C89 conformance
Fix spelling errors in the header file
Update the header file to reflect the changes since the original release
Move the putcf type definition to the header file
Merge github.com:nmlgc/tinyprintf
update doc for long long + size_t support
add doc specific to tfp_format
moving tests to new test/ subdir
rename printf.* -> tinyprintf.*
allow to selectively compile-in printf/sprintf
tests to make sure tinyprintf compiles with various TINYPRINTF_* combinations
add snprintf/vsnprintf/vsprintf + tests

Note that these functions are supposed to return the number of chars
stored, this changes slightly the data structure they pass to
tfp_format.
set explicit C linkage
let gcc warn when printf params types don't match format