Configuration to disable floating point (#49)
* more thorough removal of float
* fix for stricter compilers; latest XCode/LLVM
* more progress on disabling float
* added general float test; some bug fixes
* bug fix; function documentation completed; tests
* General float encode tests when preferred serialization is off
* Code format tidying; trailing spaces
* spell check floating point section
* Code size and check #define combos
* miniscule spaces fix
* restore qcbor.h
* float test header fix
* Add base float decode tests
* correct sizes in readme
* Clean up some floating point tests TODO:s
* big improvement to preferred serialization tests; variable name tweak
* more tidy up of preferred serialization tests
* more float test tidy up
* remove conversion to subnormals; tidy up comments
* README fixes
* reformat a comment
Co-authored-by: Laurence Lundblade <lgl@securitytheory.com>