Changes:
- change doucumentation of length() and correctly represent newline
- take more care to never pass a sign-extended char to the <ctype.h> isXXX() functions
- more tweaks to fix for read() problems
- Correct input_char & update documentation for base 36 input
- return a 0 (zero value; instead of reporting an error) for the L command when the named register stack is empty & document behavior
- be more careful in specifying how the precision of the result of the V (square root) command is determined
- don't prematurely exit from stack-unwinding Q command
- ensure that DC_FAIL API value does not collide with any internal dc_status code
- clarify that Z command reports on digits in decimal representation in number (as opposed to ambiguous, perhaps "o"base, digits)
- Fix two memory leaks
- Extend input base to allow for base 36 with Z being the largest input digit. Now, ZZZZZ will be the largest 5 digit number given the allowable bases
- dc_evalstr() incorrectly used len-1, to omit counting the closing ], unconditionally, even when string parsing terminated prematurely (end-of-string reached before closing ] was found)
- dc_evalstr() was inappropriately/prematurely returning when the top-of-stack was a number
- Implement & document R, general stack rotation command
- Explicitly flush output, instead of requesting line buffering, as the user may be emitting a prompt (without a trailing newline) within an inferior process.
- Add a bc_exit() routine that resets the editline state in one place to exit. Removed editline state reset in other places.
- take a more nuanced approach to handling SIGINT
- the code is now released under GPL-3, and documentation under FDL-1.2
- detect, report (if possible), and exit with error if any I/O errors are encountered