Added 32-bit Windows build

Closes #6

Update CMakeLists.txt

Changed the cmake prequisite from 3.17 to 3.16 to be able to build atomicparsley on Ubuntu 20.04 LTS

add cmake install target

Closes: #26

README: add info on Alpine runtime error (#20)

* README: add info on Alpine runtime error

Add info on readme to help with the libstdc++ load error

* README: simplify libstdc++ fix note

modernize NSImage usage

- Fixes up NSImage to use a technique that doesn't depend on the
  DPI of the current screen and just uses pixels
- Fixes a crash when releasing the image; the crash was caused by
  a `memset` call getting a different size for the filename buffer.
  I solved this by passing the size down, which is safer than just
  assuming anyway.  I added an ASAN cmake option to make it easier
  to turn up the debugging and understand where the memory corruption
  had come from.

refs: https://github.com/wez/atomicparsley/issues/14

replace naughty fgetpos/poke/fsetpos with fseeko

fpos_t is intended to be an opaque type so reaching inside it
is not right.

Switch to fseeko/ftello which are the off_t equivalents of
fseek/ftell.

closes: https://github.com/wez/atomicparsley/issues/13