README.md: fix capitalization

README.md

 # Quickstart
 
-- compile the library with `make`
-- include the `cwav.h` header
-- use the `read_wav` and `write_wav` functions for IO
-- compile your program with the following options:
+- Compile the library with `make`
+- Include the `cwav.h` header
+- Use the `read_wav` and `write_wav` functions for IO
+- Compile your program with the following options:
     - -L /path/to/lib/directory
     - -I /path/to/include/directory
     - -lcwav