Implement atof

fcntl: open should use a va_list

Implement fcntl

The current implementation of open requires the user to pass all three
args to the function. It should use a va_list and allow a user to
provide only the filename and flags.

No tests written yet! See #36

string: fix out of bounds bug in strncmp

Add build badge to README

ctype: tests and reorganize

Wrote tests for the functions implemented in 40558b26 and maybe made that
test a little more comprehensible.

Also made sure that fmt.sh and test.sh were being executed by bash all
the time (compatibility with other shells).

Finish ctype impls

Create crate and stubs for wctype

Create the wctype crate and stub functions with the unimplemented macro.

Add ctype functions and atoi/atol

Add ctype functions
  - isalnum
  - isalpha
  - isascii
  - isdigit
  - islower
  - isspace
  - isupper
Add stdlib functions
  - atoi
  - atol
Fix some warnings
Make a fmt run