Modernize: combined PR

[GravisZro]

This PR combine the other 6 PRs.

• Modernize: build system

  • add a .gitignore for build system related files
  • remove ancient makefile (resolves issue compilation issue compilation issue #6)

• Modernize: types and declarations (Use "modern" (as of 1999) standards)

  • void instead of VOID (type standardization)
  • intptr_t instead of INT_PTR (type standardization)
  • Remove small C declarations (function declaration standardization)
    Note: support for small C compilers was already broken, so nothing is lost by removing the declarations

• Modernize: printf statements

  • Update printf statements for printing pointers.
    • Replace x%xl with %p
    • Remove pointer casts to (unsigned long)
  • Update string literals
    • Use string literal concatenation to make a series of printf statements into just one
    • Use raw string literal for long multiline string

• Modernize: use nullptr

  • Replace all instances of NULL with nullptr
  • Remove type casting of the null value.

• Modernize: replace macros with inline functions

  • Make sure all macros pass in all variables used (a mesh* type varaible (aka m) needs to be passed in for several)
  • Rewrite macros as always inlined functions to ensure type correctness

• Modernize: showme

  • Move to cpp file
  • Replace small C function declarations standard declarations
  • Make showme buildable (for systems with X11)
  • Use raw string literals for usage string literals
  • Fix errors/warnings about string literals
  • Fix a minor bug